> If you see "he" everywhere, you assume being a man is the standard, and being a woman is somehow not applicable.

I don't quite follow. Are you saying that, by using "he" everywhere, I'm going to subconsciously exclude women?

> And it's not that hard to just use "they" instead

I cannot speak for anyone but myself but, being a native English speaker, using "they" to refer to a single person sounds wrong. I understand the tendency to use it given the lack of a gender-neutral singular pronoun but it doesn't change how grammatically incorrect it sounds to me.