I've been to plenty of Food Not Bombs events where people are being fed and the prevailing attitude was, "If there are people needing to be fed, let them come and we'll feed them." The same folks were handing out harm reduction supplies.

These same folks went on to figure out the logistics of preparing food. So no, I don't think it's at all axiomatic that the people who disagree with nationalism are necessarily affluent in the slightest. In fact, I've found most solidarity with refugees and anti-nationalist movements in the working class. The overall community of folks I saw ranged across income brackets -- plenty of software engineers, tech folks, trades folks, unemployed folks...

I think that when people say, "They don't really mean it" or "their principles wouldn't stand up if it meant a disruption to their lives", they are not aware of just how much work folks are actively doing every day to live by those principles and invite people in.