The OP says tankies. Those kinds of extreme left are extreme even by non-USA standards. A European-style democratic socialist like Mamdani would be, one hopes, to the right of them. Tankies were largely forced out of European mainstream parties after the shocks of 1937, 1956 and 1968.

A better way to think of it is that the western “left” isn’t part of the global left. Using tankie unironically is a classic example.