I'm just curious.

Just played a ranked game, Singed top on my team is going against Renekton. He's not doing well, dies few times. He asks Lee on our team for a gank. After 11 minutes, he says he's "done". He then starts trolling by wandering around the jungle doing nothing but taking camps and then walking into lane sometimes to die, saying that he's doing just what Lee was doing, wandering around doing nothing, though Lee did gank bot a bunch of times and get kills. His score then proceeds to get more negative, then we eventually lose, with nothing that I can do about it.

I'm just curious, why did I lose LP?