She included herself by using WE
Ginsburg joined the court 20 years after Roe v. Wade and 13 years after Harris v. McRae.
She obviously supports abortion (but we do not know from this inteview how long she has supported abortion).
She is making commentary on how her assumptions about the societal motivations behind Roe v Wade changed over time (and well before her appointment to the court). She is saying her assumptions were proved wrong by Harris v. McRae. (I think her initial assumptions were correct, but that’s neither here nor there).
She very well could have the same motivations for supporting abortion as those she suspected others of having. But we do not know this to be true from what she said in this interview.