The country I live in does not routinely do summary executions of leftists the way fascists and Bolsheviks or Maoists did. So to me they are similar adversaries in that neither is in power and they would both be extremely dangerous if they were. Furthermore, I think these groups who support dictatorships have strayed so far from leftist values that it's not clear to me they're still members of the ideology at all. The same way fascists tried to convince everyone they were simply an evolution of socialism. But that doesn't make it true, and Stalin claiming the mantle of leftism doesn't make him a leftist. Not even if he was one in his youth.

That's not to say I will never work with authoritarians if the situation requires it. But I do not consider them allies unless and until they are willing to acknowledge the crimes of the people they idolize. Until such time it is completely reasonable to believe they would repeat the same actions all over again if they had the chance.