How can I get my autistic sister to understand that not everyone will care about her or be nice to her?

[Anonymous]

I know she learned that not everybody is going to like her or care about her but she keeps saying they will. She thinks that if she tells people she’s autistic or has “special needs” then they will be nicer to her or accommodate her needs. She’s NEVER been so wrong. She’s attended a private special education autism school since she was five. She’s going to be 18 in October. You figured by know she would understand or get it but SHE STILL DOESN'T GET IT!!! She still thinks everyone is her friend and will like her hair because she nice. She’s sweet but honestly a softy and a teachers pet. She gets triggered and bothered that someone doesn’t like her. Our family doesn’t do her any favors by coddling and babying her. They are too afraid to hurt her feelings and tell the truth. Well a couple isn’t afraid to tell her the blunt truth. My parents have no problem telling her the painful truth. My brother and I don’t either. Since she transferred to a public high school she was in it for a very rude awakening. She thought everyone was going to be friendly and like her but she was wrong. My brother and I warned her that public high school wasn’t going to be like her old private school. She dismissed us. She came home crying and said peers were rude, pushed her to the side and even some teachers yelled at her for being late or weird. Dad was like, “I told you. I told you it wasn’t going to be like your old school but you didn’t want to believe us. She NEVER believes that people are going to rude or don’t care about her.
She’s too busy thinking about how everyone will like her, butts into people’s conversations and try to be supportive and help but people yell at her for getting into their business and nosy. How do we get her out of her head and realize people SUCK?

[Krismon]

I'm not autistic but if she's anything like me then she might be seeing the world with a set of rules, essentially that there are all these social rules of what to do and not to do and that she has memorized them and will not break any of the rules so logically she will not get any punishment or rude behaviour in return, since she is following the instructions of how to interact with people correctly.
This is just to try to offer some helpful insight though, I don't know if that's how she feels or how to stop feeling like that.

[AnonAndrew]

All you can do is tell her flat out. If she won't listen, she won't listen. Nothing you can do about it.

[Anonymous]

If she has autism she might have tough time understanding other people.

[jahaims]

You might not be able to.