No, we're not robotic, but I don't see what OCs have to do with that anyway. Writing fanfiction is a popular hobby amongst nerdy types (have you ever noticed how quickly AO3 meet their fundraising targets? If people gave that eagerly to charities the world would be a very different place), and is certainly not the preserve of autistic people. Nor are OCs. In fact if you're looking for silly stereotypes I think that 'autistic people are not creative enough to write fanfiction or make up OCs' would be a more common perception.
Personally I generally don't like OCs, as the vast majority of fanfic writers simply don't have the talent to properly flesh out and integrate an original character, but there's nothing wrong with writing them if you want to, and there is the occasional author who does it incredibly well.
It's kind of hard to figure out what you point is here, but it seems kind of like you think special interests are a bad thing(?). They're not, there's nothing wrong with having intense interests in a particular thing (such as making OCs for your fave fandom), or spending a lot of time on that one thing, so long as it doesn't impact your ability to live a functional life.
Personally I generally don't like OCs, as the vast majority of fanfic writers simply don't have the talent to properly flesh out and integrate an original character, but there's nothing wrong with writing them if you want to, and there is the occasional author who does it incredibly well.
It's kind of hard to figure out what you point is here, but it seems kind of like you think special interests are a bad thing(?). They're not, there's nothing wrong with having intense interests in a particular thing (such as making OCs for your fave fandom), or spending a lot of time on that one thing, so long as it doesn't impact your ability to live a functional life.