Martial arts do not build a lot of strength, some but not as much as lifting. You can get strength without building bulk. Have you ever worked out? I am guessing no.
Bruce Lee was a great martist artist and he lifted. He knew it helps and he was hardly slow.http://www.sherdog.net/forums/f13/bruce-lees-workout-284561/
As for Chief and Kareem this isn't the 80's. The games have changed, people work out all the time. KG and PP lift weights are they muscle bound. This is not the stone ages anymore. It will help Melo to do so.http://www.boston.com/sports/basketball/celtics/articles/2007/09/04/garnett_sweating_details/
It is a myth that lifting makes you a muscle bound and slow. These guys have trainers that prevent that. Even sprinters lift and most Olympians for each sport.http://truthonhealth.org/challenge-steps/fitclub34-challenge/
Get with the modern age, all pros lift. It helps people to lift. It will help Melo, he is weak in this area and it will make it stronger.
Ask some of the guys here who have played ball past biddy ball, in big high school programs, college programs or some form of pros. I bet they lifted, it was mandatory for me at many of these levels.