That’s their TOS. Their actions recently — namely undeleting user posts and comments — run directly counter to their TOS. They’re essentially claiming ownership of the user submitted content by doing that.
So basically, according to Reddit, they own everything on Reddit. That means all the the CP, hate speech — and in this case, piracy — that are posted on Reddit are Reddit’s responsibility. Bold strategy, cotton. They’re basically waiving their net neutrality.
What’s old is new again. I actually still prefer IRC to Discord or Telegram, never could get into it.