Given the amount of tankies running around on Lemmy, the "liberal" in question is likely an anticapitalist, anarchist, socialist, radical leftist, and the "comrade" is just an authoritarian who wishes they were born in time to lick Stalin's boots and calls everybody who doesn't deepthroat Putin's hairy balls for breakfast a liberal.
But that's just how it feels in this context. In general, yes, communism > capitalist liberalism.
In my experience tankies are just people for whom being communist or leftist boils down to "west bad" and therefore everything else must be good. I know, it doesn't make sense.