It hurts the league if they don't talk. How else do they advertise? If these guys are paid millions there's no motivation on their part to talk, but if there's a fine then they're more likely to do so.
Knowing GP, he's pissed about his role in the offense and knows if he talks he's gonna say something he'll regret, like he did earlier in the playoffs. Better to get fined then hurt the team with some controversy.
