It's a major problem in technology that really needs to be addressed if this country is going to be competitive in the future. It's unfortunate that it's so inflammatory, but it needs to be addressed.
Somehow I doubt it's particularly bad in the US tech industry compared to other countries, maybe there's more lawsuits but that's the American way. Anyway I think there's two quite different forms of sexism:
1. The belief that one sex is much better at something than the other by nature of their sex.
2. Inappropriate sexual comments/jokes/propositions that belong in locker rooms or on Tinder.
I'm pretty sure the first one is mostly dead and buried in the western world, at least I've never met anyone that has hinted to a natural order where doctors, engineers and mechanics are men and nurses, secretaries and hairdressers are women. Slight surprise yes, but no more than finding a man in a female-dominated occupation and never questioning their capability.
The second kind, well IT tends to attract people who are short on social antennas. Not that they're particularly wanted, but they don't get work in "people jobs" but as long as they can operate a computer they can do a tech job. That often means they haven't bonded on an emotional level and only think about women as objects for sex. Maybe they have experience from casual sex or prostitutes that reinforce that view.
Then there's the whole man-woman dynamic, for the most part men want sex and women relationships so the proposal is likely to be far more sexual. When a woman indicates she's attracted, most men will be flattered. When a man indicates he's attracted, many women will be insulted. Basically I think women in general are far more sensitive about unwanted sexual attention or objectification than men are.
P.S. Once me and one male, one female coworker had a conversation that started about her "cracking the whip" and it took a BSDM turn. And even though tolerances are higher here than in the US, I was wondering if this one had gone out of bounds. Then she took it to the next level with one of our other male coworkers as her leather gimp and a strap-on. I guess he should be the one suing about sexual harassment, if only he knew...