>"Like-minded individuals" and people who share your citizenship are not the same.
Of all the people in the world the people geographically close to you and that share citizenship or nationality are the most likely to think like you or share goals that benefit both parties.
That is obviously categorically false, as evidenced by the political polarization within the US, as well as the large number of minority groups across the world (including in the US) who get persecuted by their own governments and fellow citizens.
Even if nationality is sometimes moderately correlated with the values you hold, when a stronger correlation exists, your alleged ideological commitment to forming in-groups and out-groups based on shared values should mean that people have the right (or even obligation) to discriminate based on non-nationality-based factors (e.g. liberals discriminating against conservatives in tech).
No, I said more likely to share, not will share. You can still disagree with your countrymen.
Nationality is correlated with the values you hold in the broadest sense. Easy example: a natural born citizen in the US is far less likely to believe in the validity of Sharia law than someone born in an Arab state.
In even more abstract terms, what is good for you is likely to be location dependent. People in Germany have different problems from people in the US or France, and those are different from African, Asian, and South American countries. There are of course common trends, but to pretend all of politics is some shared set of problems is ridiculous.
People discriminate based on traits all the time. Liberals in tech do discriminate against conservatives (or perceived conservatives) all the time. They are free to do so, most people don't see many things as something you can protect as a class.
Of all the people in the world the people geographically close to you and that share citizenship or nationality are the most likely to think like you or share goals that benefit both parties.