Smart shouldn't have gone for the quick shot - no reason to do so unless it was an absolute guaranteed dunk. Even if he did score, there was way too much time on the clock for MIL to get a good shot.
But it should also be noted that Smart was also not at fault on the Portis rebound either. If you watch it in slow motion from the front, Smart was clearly going to get the rebound until Brown totally 'fouled' Smart on the loose ball. I know many people do know this, but it wasn't completely clear in real time.
But, whatever, who cares? The team sucked all year in the clutch, so I don't know why we thought they wouldn't continue to do so.