For instance:
> Noting how if two women are talking to each other at a conference, it becomes highly unlikely any guys will walk up and join us. If three women are talking, forget about it.
Yes, indeed, and there are a number of reasons for this. From my point of view, I would avoid approaching a group of women talking by themselves since I'd be the odd one out.
> My “mentor” told me he had never worked with a woman before and wasn’t sure how to talk to me. I suggested he try talking to me like a person.
Depending on the tone, it may mean something completely different than what you are trying to say.
In fact, to me, it looks to me like he was talking about an insecurity he has, and it's not directly related to you... and you are tagging this as sexism.
Long story short, there is a clear line between acceptable and unacceptable behaviour, and that is respect. It's clear that this line was crossed in a number of times in these stories, but just because you are in a position where you didn't like something doesn't mean the line was automatically crossed.