Are chat logs all that matter?

I'm just curious if Riot takes into account anything besides chat logs. I have people intentionally try to kill me as my support (thresh intentionally lantern blocks me, I die, won't help me in 2v2's), but because I say something negative to them for their behavior, I'm punished? Just seems like a flawed system when people who are actually ruining the game by their actions can continue to do so without repercussions.