>You’re comment and a sibling both express that these messages are off-putting to international audiences?

Non-American distinct from both of them here: They're right.

>black people definitely experience racism elsewhere

Persuambly you think BLM is a generic "Racism Bad" message, so 3 things to say about this

1- BLM is not a generic "Racism Bad" message. It's the name of a movement whose leaders used donor money to accumulate personal wealth. It's the chant used by protestors who burned down homes and stole from people's business. It's the motto that people who write books to argue that disputing a racism accusation is a sign of guilt and fragility. I consider myself a non-racist, and this movement is not the kind of things I support.

2- The kinds of people and media outlets who support BLM tends to be selective and hypocritical. Wouldn't an honest person who shout "BLM" when a black man is killed by a police officer, wouldn't that person also be obligated to shout "White Lives Matter", WLM, when white innocents are killed by a black criminal because of their race ? This last event happens to be a real thing that actually happened (https://en.wikipedia.org/wiki/Waukesha_Christmas_parade_atta...), by a self-confessed black terrorist. Searching for "Black Supremacy", the only response in the first page is a short Wikipedia page, the rest is articles talking about White Supremacy instead. I have a feeling things are not so balanced here.

3- Even granting that BLM is a good moral cause to support, how is it relevant to a tech document ? Let us grant the following causes are all worthy of moral solidarity ["Climate Change", "China's Treatment of Uyghur Muslims", "Sexual Harrasment", "Child Abuse", "Animal Cruelty"]. All of the elements of this list are morally abhorrent things to me that I want to prevent or reverse. Now, where and when should I say this? at my home? to each and every one of my friends or family ? at work ? on the street ? Is there any time and place where I can safely lie down and not speak about atrocities, for once?

>I’ve seen plenty of tech companies with Ukraine banners on their websites

I'm very very annoyed by this too. Seeing Github and JetBrains issue a statment about this conflict is the most pathetic, hypocritical and forced thing I have seen in a very long while.

Point 3 above applies to it straightforawrdly with no explanation, point 1 and 2 also apply as follows

1- Pro-Ukraine sentiment isn't a neutral "War Bad" message, it usually encodes within it pretty dubious and very partisan assertions, such as the belief that all Russians are to - and should be - blame and punish for Putin's action, as well as unhealthy and fanatic support for the Ukrainian government and its actions.

2- Tons of countries, everywhere and all the time, have experinced invasions and other illegal military actions. The example off the top of my head is Yemen. Children dying of starvation, civilaians bombed and hospitals wrecked, *Since 2015*. Did any of those companies issue statments then ? Let's forget about the past. Do we have a right to expect those companies to protest every single war and illegal military actions, regardless of the position of US politicians and US foreign policy, in the future?