Personally I don't think "hate speech" should be a bannable offense at all. I think riot should focus a lot more on banning trolls, intentional feeders, etc moreso then banning people who do a bit of trash talking. For example, I think dunkey's ban is B.S., especially if the malph didn't get banned too. Whatever ban dunkey got, malph's ban should have been 3 times as long. That kind of trolling, especially in a ranked game, is fuckin garbage.
And for the record, I don't consider trolling to be going sated devourer zilean jungle, as long as you try your best. Hey, we are allowed to have fun in this game, right?
But I think trolling, intentionally feeding, etc should be taken way more seriously then it is now, and hate speech less so. I think you should be able to be a dick (especially if it's in the name of putting an enemy player on tilt)