At a deeper level, content moderation isn't about stopping hate speech and harmful speech. That's just chasing the symptom, not the cause. The cause is a certain type of mentality that becomes obsessed with the idea of beating their thoughts into the fabric of the universe, no matter what it takes. These are the ones who stoop to spamming, flaming, mocking meme GIFs, hate-speech, death threats, etc. (and generally spend all day online posting such things).

This is why Reddit has been so successful. Community moderation is much more effective than top-down moderation at combatting people with this mentality, because it discourages them as soon as they show their hostility, not once they have passed some threshold of badness.