"Diversity" in this context is a politically-correct way of saying there is a large community of well-educated Indian immigrants on H1-B Visas living in Silicon Valley and working in the tech industry. Not San Francisco as much, but the South Bay (Santa Clara, Cupertino, San Jose, Sunnyvale, etc.).
Or maybe they meant the large established-long-before-tech Asian communities in Sunset & Chinatown, the Latino/African American communities in Mission-Bayview, the Eastern Europeans in Richmond, or the Italians on Russian hill, the Russians sprinkled around Goddard, or the Vietnamese community in San Jose or .... I could go on and on.
If all you do is focus on tech its really easy to miss the massive immigrant enclaves that have formed in the Bay Area and won't be driven out so easily.
Of course the Bay Area is actually diverse. But I’m skeptical that tech companies actually care about these communities. They care about close proximity to a large population of engineers.
I share your skepticism but take it a step further: can corporations actually care about something other than money? I don't think it even makes sense to anthropomorphize organizations that are governed by profit-before-all shareholders with limited liability and directors with a fiduciary duty to maximize returns.
At the end of the day, the workers the tech companies are competing for do care and that's what matters.
I think it is more about the attitudes than the numbers - there is a neophillia and xenophilia that is pro-diversity.
They don't seem to particularly care about the resulting demographics and occasionally get caught with insensitive assumptions like algorithms that fail to detect dark skinned people due to bad assumptions about how light reflects but they don't like the close-mindedness of xenophobes and homophobes.
