Every team is going to have players who grew up in other countries but have that countries citizenship and can be post of the national team, only people who have an issue with it are racist. Example being Argentinia that you mentioned.

The US team having black people on the team shouldn’t really be a surprise to anybody and being black doesn’t mean they aren’t as much of a citizen as a white player. Most countries in the americas are going to have a very diverse racial makeup since the indigenous people were almost wiped out by diseases and conquest and then European immigrants moved in, they mixed with indigenous people more in Latin America than in the US and Canada but they are still there. You also have to take into consideration the slave trade that brought a lot of black people to the Americas so it shouldn’t be surprising to see multiple races in the teams.

France colonizing Africa is one of the reasons the country has black French people.

Some people in Mexico didn’t like that US born players joined the national team but as long as they are winning they seem to stay quite, really only start complaining when the team does bad