While your point around tacit acceptance is a good one I don't know if it follows that it's productive/appropriate to inject this debate into all of these situations. For one, the exact issues you care about could be very different from someone else's and having all these discussions is pretty distracting.
The method in this case, writing an open letter, seems like a way to weaponize network effect and have an outsized influence over say simply talking to your manager or using an internal feedback system. I think SpaceX is right to say this causes social pressure internally to sign on and not be on the wrong side of the "if you're not with us you're against us" attitudes of politics today.
No, internal channels can accomplish these things as well. Or political initiatives and lawsuits. Saying that the only choices are a larger open letter type airing, or else an exploitation of minorities, that's a false dichotomy and the tired exaggeration.
The method in this case, writing an open letter, seems like a way to weaponize network effect and have an outsized influence over say simply talking to your manager or using an internal feedback system. I think SpaceX is right to say this causes social pressure internally to sign on and not be on the wrong side of the "if you're not with us you're against us" attitudes of politics today.