It's not about what's most important to one's identity, it's about what's more harmful in present times. Racism is still deeply
harmful, in a way that making fun of the French/British/Americans/whatever isn't. A lot of the latter just devolves into mostly good-natured international ribbing, about Yanks being fat, the French being smelly, British food sucking, etc.
Also, it's easy to say that one's perceived race isn't important if that's not an issue that affects you, but if you were black and were experiencing frequent racism from people merely looking at you (not otherwise even interacting with you in a way that could allow them to determine your national identity), then you might sing a different tune. I'm a white American, and my experiences at home and abroad are much different to those of black Americans, for reasons having everything to do with perceived race. In most countries you will be treated substantially differently if you're visiting as a white westerner vs a black one. That has nothing to do with national origin and everything to do with racism.
Anyway, point is, all the differences I identified plus all the ones you identified mean that the two are quite different and aren't equivalent.