Two things can be true:
1. The Celtics are shooting too many 3s and missing
2. The refs over the last two games have literally called everything against Boston and when Boston does decide to be aggressive, they either get a foul called on them defensively OR they don't call a foul on the opponent when Boston is driving.
I'm sorry but I hate these arguments that "we're doing this to ourselves with the free throw discrepancies". No we aren't, the refs are calling a different game for Boston and the opponent.