What can be done about intentionally feeding?

I suppose this is more of a rant , but I've held these sentiments to myself for some time now. Having served a few punishments myself I now understand the chat restriction system, but can honestly not figure out how the intentionally feeding one works. I am no saint, having trolled on smurfs when I was upset before nor do I claim to be one - I am simply confused about the state of griefing in League of Legends. With no tribunal and Riot Support ignoring hard proof of intentionally feeding, what can truly be done about this issue?

I won't hyperbolize the situation like many board go-ers will, but it is still an issue that really kills my spirit some times. In the past three months there have been eleven genuine intentional feeders in my games. Out of those eleven, nine are still playing (two are still INTing regularly) . Of the two that were punished I can only imagine that it was due to them repeatedly saying racial slurs in /all chat. There is typically overwhelming amounts of evidence of this particularly nasty form of griefing, yet it seems that Riot continuously turns a blind eye.

I understand that typing is easier to detect, but surely anyone can see patterns with intentional feeders. Riot has plenty of resources available to them , this really should not be an issue that so commonly plagues games. Thank you for your time, I hope you have a nice day.

To add, if there are any genuine solutions that you think a Rioter might see, please feel free to share in the comments.