Trolls and how they are worse than ragers.

We all know what trolls are. I not refering the the small time ones either who might do one thing in a game to be funny and that one thing wont affect the outcome of the game. I am talking about the people who pick zed ADC bot lane. I am talking the people who join a game just to feed. I am talking about the ones who ruin games on purpose. We all know them, we have all seen them. And yet they are there. Why is that? Because riot does nothing about them. They ban more people every day for raging or cursing at their team than they ban those who ruin games for everyone! Not only that but I find it intresting how trolls can be a source of the rage. So a person who was a victim of getting trolled will swear and cuss and scream and shout for having his Ranked play destroyed that game, then be the one who is reported or banned. This system is messed up, and while I don't condone raging (I do it myself from time to time however) I think that this whole issue should bbe looked at.