He failed to block out on a FT, so Cronin pulls his best player in the game - the one who got you the 7-pt lead - for the final 2.5 minutes - and the last play wasn't even designed with him as an option.
A coach has an obligation to the whole team, and once the ball is in the air, that obligation is to put them in a position to succeed. Cronin deliberately did not put his best team on the court for the last 2.5 minutes in order to teach one player a lesson -- or more probably, because he was just mad at him. He was prepared for the team to pay for one guy's mistake.
Chew the guy out, make him run for an hour in practice, etc. But this was over-coaching reminiscent of late-era Howlandism. And thinking it's all part of some grand plan that comes into fruition late in the season seems to be rationalization.