It's mostly because of religion really. You see, people in ancient times dug holes in the skulls of the mentally ill to let the "demons go out." Now... I do not know how to react to this. Here is a detailed history of cultural view of mental illness.

People never understood the brain as an organ. That includes people from ancient Egyptians to poverty class till now in less developed countries. The belief that people with mental illness are bad passed down from generation to generation. And even today people think people with mental illness are violent. Not everyone with mental illness is violent.

I can give a personal exam. Since I started showing symptoms predominantly at the end of 10th grade (I was hearing voices by that point), in 11th grade I became a psychotic mess. I somehow managed to pass 11th grade and enrolled in a coaching class for 12th grade. Both the teachers and students slowly realized I am mentally ill. The teachers 'made the situation better' for the girls after reassuring the girls that they will possibly beat me if I do anything that harms girls.

I was a never a fan of rape or sexual harassment. I never groped a girl. In fact sometimes I prefer boys due to this reason. In the end I did nothing to girls even in my psychotic state, yet I still got angry looks from them. Granted I do not know how to behave, but emotionally abusing me won't lead to better results.