Best retort to "he made it so he should shut up..."
Although I personally believe that all this is a publicity stunt to make up for the fact that he was going to be cut from the 49ers anyway, I do believe that it casts light on some ongoing racial issues in America.
You see, when a black person fails to succeed, and is unemployed and/or engaged in criminal activity like illicit drug use, the usual talking points are that it's because they're a "loser" or a "thug," just looking to get "free stuff," and that they should be imprisoned if not shot dead in the streets. But if a white person, particularly one of certain political or religious affiliation, suffers the same fate, then that's the fault of "the economy," or the government for failing to give them a job, or Obama, etc.
Likewise, if a black person achieves but doesn't comply, then the rhetoric is (quoting Chappelle) "We never should have given you n*****s money!" as though their success was a gift from society that came with strings attached. But if white person succeeds, they're always self-made, even when they inherited every dime.
Now for sure, not everyone in America feels that way. In fact, the majority do not, and hold to the same ideals of equality of opportunity and equal protection of the laws that this great nation was founded upon. But for Trump and his supporters, the notion that some Americans are second class citizens due to accident of birth or failure to comply to a certain belief system, is simply how they choose to define the concept of "freedom."