When someone in a social group continually refers to females in a different way than they do to males - they could just be using the pronouns 'he' and 'she'. They could also be using the phrase 'stud' and 'slut'. A bias is not a micro-aggression, because there's no aggressive action. I can have a bias for chocolate ice-cream, does not mean I am being aggressive towards vanilla and/or strawberry. That's just bias.

The problem comes with perpetually focussing on the behaviour of other people as 'aggressive'. That's 'mind-reading' which is a really bad way for humans to live their lives. If you spend additional energy interpreting the behaviour of others as either 'micro-aggressive' then you're generating a hostility that may not exist outside of your own brain. You may as well sit down and percolate in a bath of misery.

And if you're fuming about a micro-aggression that hapepned to you, then you're probably emitting micro-aggressions to other people. It creates a circle of people all worried about offending and not offending each other. Either call people out and make it an actual aggression, or live with it. Those are really the only two viable and healthy options. Alternatively ranting, which changes nothing.... or raising social awareness, which is basically social validation for non-action. "Did you say anything when he was rude about women?" - "well.... no, but I was conscious of his micro-aggression"