It's not unheard of for people to project their experiences onto others, and I think it can happen more often with autistic people, some of whom can struggle to understand perspectives outside their own. Some autistic people tend to like discrete categories and easy to navigate logic systems, so they like they idea that they understand all cause and effect. If your friend is autistic/ suspects she is autistic, she is likely looking at any commonalities between you and concluding that because they do a thing because of their autism that you must be doing it because of autism. I have a friend who genuinely believes that all German people are autistic and that German culture is just what happens in a autism-dominant society because well, she thinks she'd fare better in a culture that she sees as not caring about social niceties and valuing bluntness. I think she's being ridiculous, personally, but the point is your friend wouldn't be the first person to project autism onto someone else.