Isn't it both? There are only X spots per school. Every person being helped up and admitted is someone being pulled back and denied. I have no opinion on this debate, but school admissions are a zero-sum-game, afaik.
This might be true for college admissions too, if you're flush with opportunities you're still ahead if you lose one.
But there's still an aspect of "pulling people back". It's a hard tradeoff to design. But if you do it right you really can make something with better outcomes and more fairness, even if some will call it an abomination.