Leave your job because tech companies have contracts with the government/"defense industry" and also pay taxes.
Don't buy anything from the grocery stores.
Cancel your flight if it's on an Airbus/Boeing.
Otherwise, it's all empty talk. To be clear, it absolutely is in my opinion.
They might also believe that invading Ukraine is uniquely bad because it is a developed western nation within mainland Europe, setting a terrible precedent. Or they might simply not have thought very much about the contradiction. And I note that you're lumping every western nation under the same category when some are much less objectionable than others; in how many developing nations has Finland engaged in extralegal murder?
That said, yes, the costs are lower to protesting the invasion of Ukraine than protesting everything the US government does overseas. So what? The costs are lower for me to buy Kroger brand soft drinks, too, that doesn't mean my opinions about the flavor is just empty talk.
But nobody (AFAIK) is contesting that the US killed more civilians in Iraq or in Syria (or second-order in Libya) than Russia has killed in Ukraine.
Your argument is that people perceive it as okay because the intentions were good? Our government could not forsee that these people would die, it was unexpected?
Or were they unintended consequences that were foreseen? I don't believe such a distinction is defensible, if you foresee the consequence and do it anyways, you intended such a consequence.
Even worse, I think the argument is that the intentions were good because it was our rulers who did it, not theirs. Our rulers are careful and thoughtful, while theirs are evil and cruel.
That's missing the point. Nobody with knowledge of the matter is contesting that, but plenty of people lack that knowledge. This means that they're not willfully ignoring the kind of contradiction that would make their opinions about Ukraine "empty talk".
> Your argument is that people perceive it as okay because the intentions were good?
No, my opinion is that many people don't realize how objectionably the US has behaved in the past (and currently), so it's not apropos to call them out on a contradiction that invalidates their outlook on Russia's invasion. Call them out on ignorance all you like, though.