I think it mostly comes down to an uncomfortable fact:
Everything is political, in some amount.
Politics, at the root level, is just an opinion that you try to derive policy from. Just like you can't "not have an opinion", you can't be "perfectly apolitical".
An easy example is the connection between GitHub and ICE. There's a binary choice there: keep supporting contracts between GitHub and ICE, or drop the contract. Either choice is political, and there is no "apolitical" position that GitHub could choose.
You might argue that "status quo" is apolitical, but that is far from the truth; "status quo" is closer to conservatism than apolitical. Ignoring problems doesn't make them go away, so being "apolitical" can easily be construed as "status quo", and that's a clearly political stance to take.
Should it be this way? You could probably have a whole philosophy course on why everything is political, but the fact is that we really like making things political, because everything informs policy.
I can't say whether brand accounts vocally supporting the movement is the "correct" thing to do, because that's basically only knowable in hindsight. What I can say, though, is that Rust is a language (and community) built on empathy an inclusivity, so this is perfectly in character for the "brand image" of the community accounts.