Yeah, obviously context matters, if someone uses it once or twice when complaining about capitalism or economic issues, it's probably not meant as a dog whistle.

The phrasing of "international bankers" is kinda weird, like the international part isn't really relevant, and it's not really something someone would come up with in most scenarios. I think most people would come up with something more closely related to what they're criticizing.

I'd assume coming from a leftist it's probably just them hearing it somewhere and not knowing the origin and common usage. I'd definitely be watching for any other signs of antisemitism though.