There is much truth in what you say. But on the other hand, plenty of beekeepers cripple their colonies by following the advice to "pile it on as quickly as they can take it", but doing it too early in the season. Witness all the posts from September on this forum from people saying "my hive is full of syrup and there's no room for the queen to lay, what should I do?". The result of piling syrup in too early can be too few winter bees for the colony to survive, which is a deadly as underfeeding is.
It's never as simple as a pithy quote, is it. Who can blame newish beekeepers for being a bit confused.