Liberals believe in a hypothetical good communist that would not qualify as a tankie. This imaginary communist was cooked up by liberals out of first principles for how they believe a communist should act and behave, because the core instinct of the liberal is to accuse their enemies of being secret right-wingers who are lying about their intentions. The hypothetical good communist would have ideals that we would say are similar to an ultra-leftist, or the completely fictional "patriotic communist" thing. As in:

• rejection of association with any current socialist state
• rejection of militant organizing
• rejection of any intermediary stage in the progression towards communism. Immediately abolish the commodity form
• complete agreement with the western world order

So under their metric for a non-tankie leftist, Che Guevara would be a bad communist because he seized state power and used violent means. Whereas a good communist would be someone like Vaush, an internet streamer who advocates for the election of Democrats to public office.