It Just Doesn't Make Any Sense

Are Keith Van Horn and Aaron McKie actually out of retirement? When the Lakers traded for Pau Gasol I noticed that they traded Aaron McKie, who I believed was retired. Now in the Jason Kidd trade the Mavs are trading Keith Van Horn who is also retired. I do not completely get how the NBA can possibly think that this is O.K. Keith Van Horn will never suit up for the Nets, just like McKie never suited up for the Grizzlies. If the NBA allows these kinds of shenanigans the Celtics should sign Dee Brown and trade him for Ron Artest. I mean that is the logic that is going on here now? Right?

I mean I think this whole trading thing is as logical as this: