I think you misread "meritocracy" as a good thing. Meritocracy is pretty much Ayn Rand's ideal society: the truly talented, superior people rise to the top and dominate the lesser. This is an uber-capitalist notion: the ubermensch pretty much can't be nice to inferiors, because that opens the door for cronyism, nepotism, etc.

By contrast, communism would be the ultimate expression of sharing, cooperation, etc. but it ignores people's skill in the distribution of value. The old maxim, "from each according to ability, to each according to need" means that someone who is paralyzed and (would have) massive medical bills receives free treatment, food, etc. to stay alive. Obviously this comes from more "skilled" people - doctors - who in a meritocracy would instead extract the maximum value from their skills.