The misleading nature of the Tweet to avoid putting the numbers in context. It's a drawdroppingly low number for those of us in cities that even the rest of the U.S. considers overpriced. That's what he's playing to, the people who will be shocked by the number using their own hometown as a frame of reference.
He's not Tweeting any context like that it's X% below median SWE wage in Warsaw. If it's still an insultingly low wage even by the standards of the area, it doesn't hurt to put it in context.