(I'm not from the US, perhaps I'm missing something?)
The phrase 'Black Lives Matter', or movement thereof, I think is reasonable and agreeable to all but the most vile of people. Ignoring them, it's something all agree with.
The problem arises as with everything in life in that it becomes politically charged and coopted. There doesn't appear to be a cohesive organization behind it, so you get fringe(bordering on hate) groups supporting it. There are tons of videos on YouTube, no need for me to enumerate.
It's really not fair to anyone. It's like how the OK hand symbol is considered by some as a racist dog whistle, because some assholes coopted it.
Sadly, what's been coopted here is much more important than a hand gesture.
I mostly think people on both sides of this specific issue are people who focus on different sides of the movement. In good faith, I assume the Go team supports the phrase, as is. The detractors probably see all the media around the co-opters, and decide they want nothing to do with it.
Nope. I support the BLM cause, but it doesnt belong on a programming docs website. Or at least, not on every single page. Put it on the homepage, and be done with it. Having it on ever single page, for years on end, is insufferable.
I was trying to answer more in the scope of the question asked. I think the vast majority of sane people would say 'of course I think that black lives matter." Why that became politically charged I tried to answer somewhat neutrally.