That’s honestly what I would have assumed as well. Especially since I know this guy is very well geared and generally rolls with groups that are in the same boat. I assumed his change of heart may have been that he initially agreed to roll because he actually didn’t need it, until he realized he could just sell it.
Regardless of his change of heart, he still dropped the ball, the warlocks loot is now the warlocks loot. Asking for someone’s loot and kicking them for not agreeing to hand it over is the real scummy move.