Culture in itself has nothing glorious to it. Just because something belongs to a culture or cultural traditions doesn't make it great. Stoning as a reaction to adultery doesn't sound great to me, for example. Nor forcing a marriage by raping a girl. Nor treating your wife as a slave. Although this is part of some cultures around the world.
People do look for a sense of belonging. This could be provided by a form of nationalism, but can also come from your family, local community, groups of shared interest (supporting the same sports team, being on nostr, etc). I can relate way better to some people belonging to different nations, where we have the same interests, than to most of my native fellow country men.