Some Liberals, Trots and Conservatives, believe that the CPC is communist only in name, and has followed the path of many former communist parties and went to the right (Becoming Socdem or Neoliberal, or whatever happened to Cambodia), like many Eastern European and African Parties.

So by calling Xi Marxist-Leninist, they are saying he pushed the party away from "Democracy" and back into Marxism-Leninism, which is "bad" because gommunis is ebil.