Why do many people have misconceptions about my autism and the type of guardianship that I am on?

Why do some people think it’s wrong to have sex with someone under medical guardianship? It’s perfectly fine and legal! It only affects medical decisions not sexual! Some people think it’s illegal when it’s not. Why do they make false assumptions. My therapist said I could still have sex even if I have medical guardianship and I can still consent even if I have medical guardianship. People on other forums assumes I can’t give informed consent because I leave out info and it’s not true. I can consent and it’s legal for me to have sex. What do you think?