The dominance hierarchy of patriarchy only started 10K years ago, a time when not only women got dominated, but men started dominating other men and we had a stratified culture for the first time, rather than the egalitarian, cooperative one we had for the prior 97% of human history. Men act like this because it’s been ingrained in them that it’s the only way to rise in the hierarchy. Bullying, sexual harassment and racism are all over forms of jousting for dominance. The good news is, they’ve only been doing it for 3% of our human past, so there’s hope for the future.
That being said, I do get tired of the incessant mansplaining and poor behavior in a place where people ought to be able to exchange ideas like civilized beings.