There's nothing offensive whatsoever about the shirt. IMO it's more about situational awareness. It's just another talking point that takes the focus off of the workout. He's supposedly being blackballed because of his actions regarding his political and social stances, and the distractions that they may bring. One would think that if he was interested in making the best impression (i.e. I'm here to play football and not create a circus), he would have avoided anything non football related.