How would it take away from his legacy? The legacy of a bodybuilder isn't built on (no pun) being as healthy as possible. Everyone understands this, because it's not healthy to be 300lbs and sub 10% bodyfat. It's built on being as great at building muscle as possible and being lean, and in that sense, he is a legend. There's tons of top competitors that are fucked up by injuries in every sport; it doesn't take away from their legacy.
Of course it is, but you could say this about many professional sports. It comes with the territory.