Game 4: Unbelievable

I played this game against a 6k on KGS. I am White and this is a 2 handicap game.

Moves 1 - 50

Moves 51 - 89

Black resigned here. Are 6ks on KGS really this weak? I'd think the 7k from my other posted game could give this guy at least 3 stones if they played. How can this guy maintain a 6k rank? It's just unbelievable. Time settings were 10:00+0:30*5, so it couldn't have been time pressure.