You're like two laps slow on your own logic, here. Since, you know, you answered your own question.
And he likes talking to the media just fine. In fact, he signed on to do so multiple times entirely of his own volition in the off-season.
What he doesn't like is being perceived as agreeing to do the bidding of rich white men. So he turns every press conference into a ghetto sideshow thinking somehow that makes him more come off more real, and doesn't realize he ends up looking like a clown.
Nobody has press-conference specific social anxiety disorder that magically transforms into sunshine and unicorns for late night TV and video game spots. Guy's a racist piece of #### and would earn a lot more respect from the people he actually wants to impress if he stepped on the podium and said, "#### you, massa," and tore up his check instead. But he's too cowardly, so he takes this path. Cuz Uncle Paul's money spends just fine, so long as Marshawn ain't got to look white to get some.