There is this popular thing to say in LoL and that is "report". For just about anything, anything they don't like it's "report". They die because they don't know to play well, they blame you and "report". You supposedly don't offer enough help - "report". You supposedly KS - "report". They lose the match - "report my team". They want to report you for just about anything, it is quite ridiculous. I know Riot do not support this kind of behavior, and it is obvious from the reporting screen where they offer to report players. They want you to report actual inappropriate behavior, not any nonsensical nonsense. And I bet they ignore around 99% of the reports. Now what I want to offer is action against these nonsensical reports, even banning players who report inappropriately. So they will have to think twice before reporting. And over time the popular "report" calling in the chat will disappear.
Riot ! You really need to get a grip on your community. It is by far the worst gaming community I have ever seen. It probably gets better at higher ranks, but I don't know as I am bronze, trying my best to climb.