Brian D, it is a choice that I respect - to make one's body adapt to the demands of one's sport is a fine thing, particularly if one is a professional at one's chosen sport.
A number of people have tried to convince me that me adding some muscle - not much in my case, just moving up a weight class - would be beneficial to the health of my aging joints. My gut tells me that this isn't true. I have gotten leaner and more muscular, both in small amounts, since I started lifting, and I'm content with that. If I put on more muscle, I'm OK with it as long as I stay in my current weight class, which means I have to lose a little bodyfat, and up to a point, I'm OK with that, too.
Different strokes for different folks, I guess. Everyone should add muscle, even a lot of muscle, if it helps them achieve their goals, and those goals are matters of personal choice.
JMO, YMMV.
-S-