Why are people from the poorest and most corrupt countries always so proud to be from there?

I know a lot of Latin Americans from places like Mexico, El Salvador and so on. Their countries are poor and corrupt. These countries are also not really all that old either. They ran away from those countries because absolutely nothing functions there. But they are extremely proud to be from those countries. They wave a Mexican flag when they protest here and so on. Why do you think they're so proud. I never got that?