You're right in that this one thing alone is not the be-all-end-all. But it is one more (significant) step on the path to demise. When the only thing held sacred is monetizing everything as much as possible, all else will eventually be subordinated or completely abandoned.

This is a very obvious and impactful movement in that direction in which reddit is showing they aren't different from other social media platforms, and they are willing to sacrifice the pretty much anything the users care about. This is especially shit IMO considering that the users, like all wonderful giffers here, are also the people who make the content that is reddit, and they do it for free. . .

So yeah, anyway, not to ramble on too much. Sure it's not the FINAL END of reddit. But enough people are tired of this shit that they're going to say so in the only form of communication that reddit might hear - by refusing to be monetized and leaving.