> Most cases of sexism aren't "clear cut". If you're the only woman in the office, it can be hard to figure out what's going on. Believe me that you try to explain certain things away and don't want to go to sexism as a first choice or a choice at all. But when you're a year in and you still notice there are very real differences in the way you're treated versus your male colleagues you have to start accepting that sexism sadly may have something to do with it.
This one is a clear-cut case of sexism. If you allow yourself to be discriminated against by a co-worker, why would that co-worker stop being sexist toward you or other women employees? at first place. Report them.
If the hierarchy does nothing about it, then it's a sexist workplace and it should be called out for it, publicly. Time isn't for inaction anymore, inaction is what helps perpetuate and normalize that behavior.
You said you had access to a group of female developers for support, did you talk about that incident to your group? Did they tell you to shut up about it? I think not.
You rightfully said females are a minority, well consider the positive impact of reporting workplace sexism, for females as a class.