Why do most people think people with autism/Asperger’s are very gullible and naive?

One of my aunts flat out told me that I’ve very naive and so gullible that I get tricked so easily and always give in so easy. Like the time her boyfriend kept asking her for money to “help him out” but he lied. She said I’m so innocent that I don’t always see what others see and I get manipulated and tricked so easily and that’s why I’m still living at home with my dad. She said it’s just best if I stayed at home until I’m capable of defending for myself and be more aware of people and be less nice. My dad even said I’m WAY TOO EAST GOING and people take advantage of me so much and takes away from me. I’ve been trapped, tricked and always getting myself into trouble. One of my cousins said, “No adult should be THIS naive unless you’re an autistic adult. Most adults are more aware and less naive.”