I don't know much in depth here, I do have opinions though. I have been around Pittsburgh for 25+ years now and I see how an organization like the Steelers or Penguins that is committed to winning behaves. I also have seen how the Pittsburgh Pirates have treated their players.
Really the way the NFL is run now, playing for an undervalued contract is unprofessional. If JP had gotten hurt such that he was unable to continue his career do you think the Bills would have paid him his full contract? I also would state that he got what he wanted, didn't he? And it's not like the Eagles are the Raiders.
I have never heard anything from JP other than he wanted to be paid appropriately for the position he was playing. The question was where in the pecking order of that position do you put him. The Bills did make a great commitment to him when he first went from TE to RT but nothing when he went from RT to LT, and from what I can tell that's where the issue is. He played what, 2 years at LT before contact issues came to a head.
My point is that when the organization does not value winning first, the players sense that and look even more toward the financial side. There aren't hometown discounts from the top players. I thought JP's comments were very telling about some of the attitude in the locker room. This all sucks for the fans, but it's what we have. You can put as much blame on JP as you like, or talk about how he is going to balk once his contract gets outdated, but unfortunately for us he played the game and in the end he won and we lost.