why do people think its okay to ruin other peoples ranked experience by trolling?

I was playing ranked on my smurf and picked Yi top (all things aside, ive done well with yi top hes not awful its just fun and alot like trynd or kat) and this guy starts ranting off about how much hes gonna fuck me over if i lock in Yi, so he picks kayle goes top with me and does exactly that. pushes lane forces over extension in lane...

of course we lose the game, but the best part was i got flamed and reported for not picking someone else or going to a different lane...

Mind you i was 2 picks ahead of our kayle... so he knew i was top.