Wtf is wrong with people?

I just had a trynd jungle that refused to pick smite and said "ignite is better". I literally can't tell if he didn't know what smite did/what jungle items did or he was flat out trolling. He was most likely trolling though as he was yelling in all chat to get me reported for griefing even though I did everything I could that game. So what's wrong with people and what goes through their brains? And why are people like this allowed to play ranked?

( No this didn't happen on the account I'm posting on )