> People are tribal by nature
This is "appeal to nature" nonsense. Tribalism, just like every other social behavior, can be learned and unlearned.
Imagine if someone was getting tribal along odd VS even apartment number or floor number. It would be seen as ridiculous just because it's not in line with the social construct indicating what to be tribal about.
> People group together with others that share certain cultural values.
By this logic, relocating across countries should be made illegal to prevent diluting culture. This would be ultranationalism.
> I don't feel culturally similar to many other European countries
Societies are not countries and are not people. We can be feel very disconnected from some societal values and yet find similar minded individuals in it.
> Grand unification of humanity is a good ideal, one we should work towards, but it's not something that will be possible within our lifetimes.
Citation needed. Humanity has never seen the level of culture and information sharing that is happening now.
For the first time in history some 15 years old girl in Vietnam can watch at a viral meme put on social media by an equally young boy from Canada. Practically for free and with no effort.
> Such political differences don't just disappear.
History shows otherwise. Big, unexpected grass-root social changes happen. Especially under the pressure from climate collapse and so on.