The fact that it's happened before doesn't make it a good thing, and doesn't make it something that shouldn't be opposed.
Fortunately Reddit is well-archived so LLMs can still be trained off of it, regardless of what Reddit or its users try to do to the data now, but it's still a negative thing that doesn't have to happen.
"It's ruined and that's a bad thing, so let's ruin it more. Including the older stuff that wasn't as badly ruined."
This is a very childish approach to life, IMO. If you don't like Reddit any more then just move on and leave it be for those who do still like it.