Why do we have to lose LP when someone disconnects at 4 minutes?

"Hey Riven, can I get a leash? Oh, okay. I'll just solo this buff. Hey Riven, want a gank? Well, I got her flash for you, all by myself as you stood still and watched, so that'll make things easy for you. Oh, you died anyways? Well, there's always next fight, I guess. Oh. You left the game? Well, fuck you too."

Thanks for wasting my time AND lp.