You stand your ground girlfriend! It has nothing to do with her.

If you don't feel like you can confront her (and like Mel, i'm not the retiring type - but there's a time and a place). Maybe just catch her as she's leaving, while she's on her own I mean, and tell her that you really don't appreciate the comments and that you come for support. She's free to parent as she chooses and you don't comment on that so you should receive that respect too.