Bruce Ratner is not Magic Johnson, in spite of their love of the game and Brooklyn. Ratner has the support of a key group in his drive to get his planned Nets arena and mini-city built: affordable housing advocates. Those advocates picketed Magic Johnson this week as he began selling luxury condos next door to the arena site. Just how powerful those advocates should be is a matter of some debate. Also, critics have a new mantra in the Brooklyn Nets debate: Move them to Coney Island!