If you're going to make an assertion like this, it helps to have the history straight.
Steve Bisciotti was fully behind Rice and didn't want to impose greater punishment, but once the video came out the NFL forced his hand. He has been supportive of Rice throughout the process and went public that Rice deserves another chance in the league.
In that sense, Giants treating of Brown looks to be more severe than that of Rice if you compare the timelines and that no video evidence exists for Brown, but was very damning in Rice's case.
But I know, it's all about the race.