I agree, the Cavs looked like a team that knew LeBron was gone. They gave up while there was still at least a distant hope of winning an elimination game! If I was a Cavs fan I'd be mad as hell about the end of that game.
Maybe it's over-analysing it, but I thought the way LeBron played was strange. It wasn't quite a Kobe "I'm going to show you how much my team mates suck by not shooting" performance, but it had a bit of the same vibe. Last year against the Magic we saw how he came out and just relentlessly attacked even as those around him sucked. This year he had a bit of a "oh what's the use, no matter what I do if everyone else sucks we lose" resignation about him.