While I agree that the NBA has deteriorated over the past couple of decades, calling it a gang mentality may be a bit of a stretch. Have the colors really changed over the years to reflect gang colors? I doubt it. It would be more accurate to call it a "selfish" or "entitled" mentality. You could probably more accurately apply the gang label to hockey, where fighting is essentially accepted.
Make no mistake. I am not defending the current NBA, they pretty much lost me in the early nineties, when it became clear the regular season meant nothing other than who gets seeded where in the playoffs, and players whose teams were down by thirty points put on chest-thumping celebrations after a dunk.
No you are wrong: the uniforms have changed DRAMATICALLY from the short shorts of the 1970s to the baggy gansta look; and the ultra-bright colors and logos are different. Compare, for ex., the "rising sun" logo of the Phx. Suns in the 1970s with the "rising phoenix" logo today---it looks like something a biker or inmate would wear. Look at the black and purple of the Sacramento Kings, and the black socks that are so common.
Heck, just watch the home teams' "intro videos" that they play before every player introduction. It is total "gangsta" rapperism.