To me the flailing elbow that connected with Rondo's face is far more of the type of thing the league should be looking to police against. If the league was less interested in their image and more interested in the things at actually could effect the well being of their players this would be getting more attention.
Not saying Garnett shouldn't receive a fine, but in the big scope of things was he really going to choke Walker to death or anything? It's all posturing. Melo's elbow could have done some actual damage.