It is a kid's club. Within the last two years: I discovered my cto, who used to supervise hundreds at google, and therefore absolutely positively had sexual harassment training, was sending candidate engineers a code test that ended up printing a naked woman in ascii art. The answer to the code test was the number between her legs. I realized this when a prospective female engineer emailed basically asking WTF?
Another workplace had 2 female engineers, out of 8 or so. A candidate commented we had, "a lot of secretaries" and was stunned when I pointed out that 2 of the secretaries were engineering peers.
An engineering peer spent lunch speculating about whether the ceo was fucking his secretary until I stopped being subtle and flatly told him to fucking shut up.
I have more stories, but let's stop there for now. Or quietly ask female peers -- most of them will have similar stories.
Further -- like any other industry, the startup / tech world has received enormous dividends from America. From massive investments in early tech, to R&D subsidies, to R&D tax breaks, to the education of the vast majority of the employees at the companies. Demanding diversity is part of fulfilling their social compact with America, and most of the whining is the companies attempting to duck it.