If Donte told this stuff to a reporter, he'd be eviscerated. Twitter is the same thing as leaking it to a reporter. The 'twitter' thing works in reverse that way too. Athletes get a pass because it's 'only' twitter.
I think you're glossing over the key aspect. Donte is 'negotiating' in public and given his history of clamoring for attention and getting depressed because fans said mean things about him on twitter, he does not present a good image. If you don't believe his 'image' matters, well, then it's just a jump to the left and a step to the right.