I wish Wallace would zip it or at least call himself out for the loose ball foul that gave Pachulia two free throws that put Milwaukee ahead late and then the turnover that put Milwaukee up by 3 with 31 seconds to go. You can't just blast your teammates when they have reason to point the finger at you.
I re-watched the second half and I think Wallace was right and wrong. He was right that there was selfishness going on but it was almost exclusively by one guy, Bass. It was not a team-wide thing. I don't know why Bass took it upon himself to be the take over guy but in the last six minutes of the game, he held the ball and tried to create his own shot every time he touched it. He only managed two free throws.
Where Wallace was wrong is that it wasn't just (one-man's) selfishness that plagued them in the fourth quarter, it was a lot of Milwaukee playing well. It was as simple as Wolters, Henson and Pachulia playing extremely well in place of Mayo, Sanders and company. The Celtics were forced to play in the half court nearly the entire fourth because Milwaukee scored on nearly every possession and except for a handful of teams in the league, that's going to doom most teams.