This sounds wrong. Hierarchies are inevitable because there will always be differences among individuals. Leftists will design a society where these hierarchies will not be that astronomically high, to raise the bottom ceiling.

Or do you know any popular left leaning politician that advocates for full blown communism instead of just tax reform?

What you called a good point isnt, its diffamation of the left. And btw, imo full blown communism is equally delusional as busines-as-usual capitalism.