No one who understands and agrees with the essence of Ayn Rand's philosophy has "concern" for a lack of "empathy" and "compassion" for everyone regardless of character. That is thoroughly anti-Ayn Rand, and is a broader scope than even David Kelly's claim that "toleration" is a "virtue in the cognitive realm".

Even David Kelly said that "toleration is not a virtue where evil is concerned", let alone granting "compassion" and "empathy" towards anyone regardless of what they are. But he tried to split that from advocacy of evil ideas at the root of the evil.

Leonard Peikoff's "Fact and Value" philosophically addresses "toleration" of promotion of evil ideas as if that were a virtue. It is not. https://peikoff.com/essays_and_articl...

One can behave in a civilized manner without adopting "toleration" of the promotion of false and evil ideas as if such "toleration" were a virtue.

Over the 55 years of my association with Objectivism, many have sensed your concerns. I have recently read David Kelly's brief book, "Truth and Toleration in Objectivism." His perspective may resolve some of your questions, especially around error and evil, as well as toleration, justice, and benevolence. All Objectivists would serve themselves well to read this, assuming they can get past the dispassionate take on Kelly,

Agree, there is a difference between compassion and responsibility.
It is natural to want to help, Rand's ideas are sparse on this, but I surmise, voluntary and with rational priorities. There are many who are down, first help those with potential, then the sick and the elderly. Those who dug their own graves, 'Go to the back of the line'.

An idea I get from Rand, Your own creativity and productivity benefit others even without you actually giving anything.
Ah from Walter William~
Before capitalism wealth came from looting, capitalism made it possible to become wealthy by providing services.

It is not possible to identify with and sympathsize with characters like Dagny Taggert and Hank Rearden in Atlas Shrugged while feeling "compassion" and "empathy" for their tormentors. Justice is incompatible with compassion and empathy for people regardless of what they are.

Ayn Rand knew very well what kind of choices people make as they develop. Understanding that is not "empathy" and "compassion" for the evil.

In Atlas Shrugged she illustrated early developmental stages in the contrast between the young Dagny and James Taggert in the same household, which was about children growing up, stylized in romantic fiction. The Fountainhead contrasted the independence of college age Howard Roark with second hander Peter Keating.

She had great respect for human potential, basing her ethics on the standards for living to achieve individual happiness, and was optimistic about the capability of people to live up to their potential.

She evaluated adults in accordance with their character and actions, which is not explained as "undeveloped child in adults", as if it all reduces to pop psychology.

She understood how Americans in particular held to the American sense of life in spite of the dominant assault by the intellectuals who follow bad philosophy -- “Don't Let It Go,” in the anthology Philosophy: Who Needs It (but emphasized that this sense of life cannot last under the withering drumbeat from the dominant intellectuals).

She wrote important articles on formation of a philosophical outlook. "Philosophy and Sense Life" is reprinted in her anthology The Romantic Manifesto https://www.amazon.com/Romantic-Manif...

“The Comprachicos” is in her anthology The New Left: The Anti-Industrial Revolution, later reissued as The Return of the Primitive: The Anti-Industrial Revolution. https://www.amazon.com/Return-Primiti... This article provides a moving analysis of how children are damaged by the influence of bad education promoted under bad standards.

She also wrote about the importance of freedom of choice in education in "Tax Credits for Education” in
The Ayn Rand Letter

Leonard Peikoff gave lectures on education of children, reissued in book form as Teaching Johny to Think: A Philosophy of Education Based on the Principles of Ayn Rand's Objectivism. https://www.amazon.com/Teaching-Johnn...

Her position and capacitance for expressing justice I've never questioned. What I do question is her understanding of how humans learn to be what they develop into emotionally and intellectually. To have empathy or compassion for likenesses of James Taggart or Lillian Rearden does not in any way allow for capitulation to inequitable behavior, only an understanding of how this behavior may have originated. Perhaps it is in the difference of treatment of children versus adults. Rand never had much occasion to mention kids and may never had occasion to see the undeveloped child in adults.

Ayn Rand had a fundamental capacity for justice. She she did not and could not have empathy or compassion for a James Taggert or a Lillean Rearden. She had a lot of sympathy for Eddie Willers, who she said was one of her favorite characters.

You were there....fantastic. About 1-1/2 years ago I procured an original copy of this lecture. UW has become the antithesis of that lecture over the years.
Tao te'Ching was my first exposure to philosophy...13 y/o. Same year Morris Massey lecture on values development, Anthem, Foundation series by Asimov...everything I could find from Edgar Rice Burroughs. The following year was Fountainhead and AS. All were formative in their own way.
Not until a decade ago did I come upon Objectivist's Ethics. I found validation in my perceptions as early as my 7th year of life. I found reason in my conflicts with others....much had to do with my lack of being able to express myself in understandable context. As reason-abled expression has developed over this past decade, and understanding that every other human IS what they learn, I have found a profound compassion for humanity. That, compassion, is missing from everything I have processed from Rand. I begin to wonder if she, by nature / nurture, has a fundamental diminished capacity of empathy.

It's best to read what Ayn Rand said herself. Her ideas covered all the main topics of philosophy in a systematic, hierarchical way; they did not start and end with politics or even ethics. Her own "Introducing Objectivism" was presented in answer to a request for the "essence of her philosophy while standing on one foot", which she did under the headings:

1. Metaphysics: Objective Reality
2. Epistemology: Reason
3. Ethics: Self-interest
4. Politics: Capitalism

https://courses.aynrand.org/works/int...

That provides her basic principles. If you meant something else by "premises" you should specify what it is. She began by looking at reality, not with arbitrary assumptions.

I remember the incident when I was studying across from the Rathskeller and large numbers of students were headed to the Fredric March theater, so I went down there and found the hallway full of listeners to loud speakers to a woman with a thick accent. I had never heard of Ayn Rand and was, at the time only interested in Chemistry, Physics, and Mathematics. A guy in a computer science class in 1965 introduced me to Atlas Shrugged. He wasn't to happy due to his subscription to The Objectivist being canceled due to asking a question wrongly. Most of it was a fear because he had just received his induction notice.
I am not sure what would have happen if I had read the book while in high school when I was reading novels that my dad had stashed under the counter of his grocery store while I was clerking after school and in the summer. Atlas Shrugged is how I started a life where an explicit philosophy was important.

That would be "premises". Start with individual sovereignty. That includes respect for the same rights of others. Her explicitly defined version of the Golden Rule is "Galt's Oath": Neither sacrificing oneself for the sake of others, nor asking others to sacrifice themselves for one's own sake. Also called "rational selfishness", which concept is sadly misunderstood and universally twisted to mean exploitation of others. "Life, liberty, and the pursuit of happiness [that includes the right to one's honestly acquired property" is closest to her ideal. Today's political notions of "social justice" (collectivist favoritism) and "equality" (financial redistribution) are the very antithesis of Rand's fundamental premises. Any questions?

I would also suggest "Pocket Guide to Objectivism" by The Atlas Society. Simple and comprehensive. Readable versions can be easily found on the internet.

Best answer is to read The Objectivist's Ethics. Presented in 1961 at UW Madison. It is the simplicity beyond the complexity of Atlas Shrugged.