That's because it's more efficient and less time-consuming. You want to metaphorically slit your wrists for potentially shit "rewards", do it yourself. Other people want the loot and get the -blam!- out of the raid to move onto other things, like LIFE for example.

I do the raid and play the game to have fun :)

I have fun when I get my loot - then I move on. Wiping over and over is irritating at best - no fun. I see games from an objective standpoint, I guess. The simplest and quickest solution for the greatest reward is the most desirable path. I only care about the end result - how I get there is irrelevant. "Cheesing" and "legit" have no meaning to me - as long as I get what I strive for, that's what ends up mattering in the long run.