Take away their safe harbor protection, since they are no longer one. If they curate, it's no longer just the comments of the participants, it's now "journalism" and things like libel apply...which would of course, shut down all the people on the "other side" from the ones they're silencing as well, and we could go back to kitty pix and meals and platitudes....in peace.
It's not just media aggregators though. Even Amazon which has displaced countless competitors censors many buyers for arbitrary rules such as "too negative". They keep a list of accounts banned from reviewing items on reddit. https://www.reddit.com/r/TheGr... They are even worse to sellers who depend on the site for their livelihoods.
Lend money to a bad debtor and he will hate you.