SIL is very much a feminist, very woke etc but to the extreme. My DD is 3.
DD is the first grandchild to ILs and first niece / nephew to my SIL. (I think) she wants to remain child free at least for now, so she sees DD as her closest small person. SIL and PIL want to take an active part in the upbringing of my DD which I'm not necessarily against - the more loving people a child is surrounded by the better in my view. SIL and I aren't very close but we have a good relationship in that we get on when we are together but wouldn't choose to hang out as a 2 without my DH or wouldn't share deep personal secrets. All this is to say that SIL is a nice person, loves DD and doesn't make these comments maliciously I think, but they still really really irritate me and I think they're harmful.
Comments that she will make:
Eg1. We are discussing schools and I mentioned in passing mixed / single sex secondary school and dating boys. SIL instantly comments "or girls if she chooses to date them!"
Eg2. SIL comes over and DD shows her some biscuits that we made that afternoon whilst DH was at football. SIL "you know, just because you're a girl doesn't mean you need to stay home and bake. You could have gone to football with Daddy if you wanted" (DD was excited to bake, she has never expressed any interest in football).
Eg3. I am helping my daughter to put on a dress (gave her a choice of 2, she picked this one) before we go to a family function. SIL comes in (we don't live together but we were driving her there so she came to our house first) and DD runs to hug her but as we've got to leave, after a few mins, I say "come on, let's finish getting dressed, you'll look so pretty". At this point DD is wearing a stained vest, PJ bottoms and one sock. SIL "that's okay, you don't have to look pretty for anyone. You look how you like! Would you like to go like this?" I'm all for giving kids choices but surely I can at least encourage my daughter to wear clean clothes and dress up for occasions? Of course I'd let her wear something else if she didn't like a dress but why put ideas in her head?
Eg4. And the "you don't have to look pretty for anyone" is an ongoing thing. I was once putting on make up before heading out for date night, SIL came over to babysit. DD started copying me, pretending to put on make up, then came up to the mirror and said "wow so pretty, like mummy!" SIL once again said to her "but remember, you don't have to ever try to put on make up or change yourself to impress a man"