Sure, any of us can point at high profile cases, but there's that old saying about anecdotes and data.
The problem with your entire last sentence is that it's full of value judgements, value judgements shaped by your experience as a human and your own knowledge and biases. One person's "hate speech" is another person's "spirited argument", one person's "disagreement" is another person's "harassment".
You might have a very clear definition of "hate speech" in your mind as you write those words, but I'd be willing to bet if you defined it here in the most clear and unambiguous language you possibly could, you'd find perfectly reasonable people disagreeing with it.
And therein is the problem - I'm on the side of that line that leaves people the hell alone in all but the most egregious of cases, because at the end of the day, it's all words on a screen.