No, no it isn't, in this or in other situations. More than two choices _usually_ exist. Statements like this present a false dichotomy in an attempt to coerce people to support a preferred position or interpretation.
Person A: I'm doing <this thing> to support <cause> Person B: You shouldn't do <that thing> Person A (or more often, C): Inaction is equal to support / silence is violence
I think there is almost always more than one possible action, even in support of <cause>. Also, some well intentioned actions can hurt a cause, so inaction is obviously preferable. Or, there may be a third outcome that I like better than <cause> or <not cause>.
Let me get specific, to avoid my own criticism.
I don't know if what the original commenter is doing is worth the effort, in terms of supporting Ukraine in this conflict. There's obviously a cost, in terms of dev time and false positives (showing the message to an unintended audience). I do think it is usually annoying, distracting, and unnecessarily polarizing to add politics to technical projects, so I would lean against doing this, even if I agree with the politics. Good technical work is hard enough on its own.
I'm not terribly offended by this action, and I wouldn't criticize it on its own; but I definitely think that "inaction supports the Russian invasion" is out of line here.