What are you talking about, I think 5-5 and likely to miss the playoffs is plenty of reason for an emotional guy like Diggs to be upset...
I don't mean this as a good or bad thing, I simply mean if in the offseason you told me the bills would be in this position, with the offense sputtering, I would have all be guaranteed that Diggs would be a sideshow diva on the sideline and I'm surprised huge blowups have not been a regular occurrence this year.
Believe me or note, no big deal to me, but I am friendly with several current and former bills/NFL players. All of them say some version of Diggs is nice but unstable.