One must distinguish between "classical" communism (Stalinism, which is dead except in North Korea) and the modern variety, which is alive and well and I think is what you mean.

There are many that think themselves "cosmopolitan", when it is a delusion and coping mechanism about being a parochial hicklib. A chip on their shoulder that makes them especially fervent acolytes of liberalism (as in: Obama flavoured, not the other kind), hoping it offsets their humble origins after moving to the big city, so folks won't get the idea that they are flyover country chuds that vote the wrong way.

A cosmopolitan, as in one that truly knows the different cultures and people of the world because he has deep first hand experience, or has read so much that it allows to draw some independent form of conclusion, is either a strong proponent of borders or a fool.

The core tenet that makes this communism-adjacent is the denial of differences: everyone is equal, "no one is illegal" etc pp. Ignorance of history and the nature of man is a must to take this position.