Any form of censorship is abhorrent. It curtails information flow and to a large extent prohibits the formation of valid and tru ideas, questions and opinions.
For example when schools prohibit the reading of Huckleberry Finn and Tom Sawyer they keep people from knowing the situation the people faces in those times. Schools don't teach about the social conditions etc surrounding the founding and early years of the country. More and more they teach that the men who founded the coutry were evil and thus all the rounding documents are corrupt and valueless.
They don tell abut the Presidents in the early 20th century who supported eugenics aimed at removeal of the Negro population in the country.
If you don't know your history you are bound to repeat it in some form or another.
All of this selective coverage of history is censorship. Political correctness is a form of censorship. Then there is the cultural censorship practiced by the varius news organizations. They simple don't report what they don't like or is not in line with the political views of the owner and editors.
Any of this is bad. it limits the functioning of society and development of true solutions to problems facing the country and the world.