It means that when everyone is equal they lose their own value because they have no individuality or they only have unstructured individuality in late stage comiunism turning into animals, theoretically at least
Equality never actually existed in communist regimes, because they wouldn’t last one day if it did, they still had incentives but the incentives were less
If you’re going to make value judgements about what choices are good and what are bad, not on the basis of their ability to reach a desired outcome, then you don’t care about individual preferences
