They don't have a choice, because Samvega is not an American citizen. They are a troll and they only thing they do is say the same exact comments in every post. Don't bother engaging with them.
Even a non American citizen has a choice in this. If they aren't American, they can't vote, but people that can vote can be influenced by the words of others (otherwise, such trolls wouldn't exist, after all, they'd have no point), and someone outside the country can still choose what to say.
I'm not really convinced that foreign operations are terribly active on a platform this small, or that these people truly are such an operation, but if for the sake of argument they are, and the user in question happens to be one, I'm not sure that non-engagement actually helps. "Don't feed the trolls" is standard advice for dealing with traditional trolls, that are just out to make people mad and will move on if ignored. But a person being paid to shape the narrative isn't going to just get bored and quit, they're going to keep doing what they're paid to do, and people are at some level influenced to align with ideas that they think are popular among the people around them, so letting them make a bunch of uncontested arguments still lets them shape a narrative through volume.
On a platform like this, that doesn't have engagement algorithms that will boost the words of someone you interact with, I feel that it makes more sense to drown out trolls of the foreign kind, so that others who see them get the impression that what they say is not popular. One just has to keep in mind, if one truly believes that one is arguing with such a person, that your goal in arguing is no longer either to refine your ideas or convince the other person of yours, but to convince other people who see the argument of them.
My point was literally that people can be persuaded to do things by talking to them (to include US citizens being persuaded by people outside the US, for good or ill). If you dont believe that to be the case, why make an argument for anything?
If you have opinions on the world and talk about them publicly in a space people in other countries can see, you do that to some extent without even meaning to.