To me, this seems to be because Silicon Valley companies are still operating as publicly traded companies. They get shareholders, they have to turn profits, and grow exponentially every quarter. They can’t risk getting into what is a very messy issue: racial politics and the police.
For every white person like me who knows how insidious institutional racism is, there is another white person with more money and power who vociferously denies it. Silicon Valley still needs white money and power — it will for a while. It simply can’t risk getting on the wrong side of it.
LGBTQ rights is an easy stance to take. So is immigration. Black-white race relations is too long-standing and too blood-soaked to be an easy issue for many. There’s no way to stand atop the mountain — like these companies did for LGBTQ issues — and just take the noble stance. For this type of issue, you have to be willing to speak truth to power — a few different networks of power — and say things that will make people a bit angry and defensive.
Give it another 100 years, maybe things will be different.