I'm a Piston fan trying to talk objectively, so take this with a grain of salt ...
Watching that footage of Tim sulking on the bench needing encouragement from Pop made me feel like the Pistons had beaten him mentally. He was so frustrated and distraught, that he just had to put his head down and sulk.
Now OBJECTIVELY, or even if I were to put myself in the shoes of a Spurs fan, last night was the PERFECT TIME for Tim Duncan to get himself EJECTED from the game. There was that horrible miss of a call when Ben raked his arm early in the game, and that was not the time to do it. But, in the second half, I think there were a couple of times where Tim got fouled and did not get the call. Even though they were not as egregious as the Ben Wallace "steal/hack," when the game was out of hand and the Pistons were about around 20, it would have been good to see Tim Duncan DEFIANT and egging the officials to throw him out of the game. Challenge the officials and call the crap and make them kick you out.
I think in a blowout loss, it could help the rest of his teammates in terms of confidence, getting an edge or a chip on their shoulders, and as a fan, I'd look at that as a highlight in a game without any for the Spurs.
As great as Tim Duncan is and as classy and non-flashy and unassuming as he is, when your team gets beat that badly, as the leader (silent or not), Tim needed to give the team a boost or a lift for game 5. Not playing for the last 6 minutes and sulking on the bench (in my personal opinion) was not a good way to do it.