Why is that?

Why is that people think a person is pretentious if they start exploring philosophy, life skills, human behavior, history, etc.?

I found myself in this situation lately, as I chose to not follow any of christian mythology established commandments, not follow any modern political beliefs, as I opted for living in virtue and have a "mother nature" approach of belief (meaning things such as diseases and natural disasters are the answer for all what humans did bad to earth and this is a defense mechanism of the planet)

I also started studying more philosophy to gather whatever knowledge that could benefit for my improvement as a person, as well as psychology to better understand what caused my mental breakdown in the past, and to improve my social skills too.

However, whenever I speak up about my beliefs and virtues, everyone calls me pretentious, deranged, idiot, retarded, egoist, etc.

I never speak about these things forcing people to believe in them, but they still act as a threat. They say the past was wrong and full of bias, and I understand that, especially when it comes to slavery, discrimination and phobia, but I believe that even if there are incorrect facts in the past, we shouldn't forget about it, or else we could repeat the same mistakes our ancestors did.

Why is that? Is people nowadays even less acceptive of the past? Do they fear that if others learn (especially kids and teens) the new generation could repeat the wrongdoing? Why is that people are prohibited to have different beliefs? Are they delusionally considering that "thinking of of the box" or "seeing things in another light" is a threat to society?