Then it's simply a trickle down effect, like for women in tech: Few choose this path so even fewer end up being tech entrepreneurs or at Google/Facebook, etc (since the article mentions the workforce of these companies).
So, once again, education from primary/secondary school is key and needs a long term investment. After that, all these talks about "increasing diversity" in tech by 'tweaking' hiring practices or what not is just PR fluff or virtue signalling because this tries to fix a consequence while ignoring the cause. Silicon Valley's giants should instead reach out to help on education if they wanted to do actual good long term.