What do you mean by "Orthodox Marxist"? Generally in American left circles, the people who adopt that term tend to think that Lenin (or if not him, then certainly Stalin) either misinterpreted Marx or cynically used Marxism to gain power, but if I am not familiar with its usage in China.
In China, those who unconditionally support Iran and Russia are usually nationalists or national leftists.
If by "nationalists" you mean fascists and "national leftists" you mean fascists who adopt superficially left-wing rhetoric to cynically appeal to people, yeah that's pretty much the same as here in America. What are you seeing that leads you to believe that may not be the case?

