If we take "brony" as a genderless term that depicts:
>People who watch, create or is involved around MLP content.

And take "Pegasisters" as an specific subdivision:
>female portion of those people who watch, create or is involved around MLP content.

This way we can fit both groups of ladies, those who call themselves/wanna be called "pegasisters" and those that want to share the "brony" definition.

P.S. If you mean anything different with "Pegasises" please tell me I may have written this for nothing while a joke flew by over my head… >_>

It's more of different and "alien" thing than any sort of superiority thing. I know some people get treated a bit differently when others find out they are a fan of the show. I would not be surprised if some people might feel superior to others because of it, but that small minority of people exist with everything. This is covered in the "Most of us don't" section.