PHILADELPHIA — This game looked very much like a two seed having its way with a seventh seed, except the Sixers and Boston Celtics looked like they flipped places in the standings. Philadelphia came out with great energy and focus, while the Celtics looked slow and confused for most of the game. Joe Mazzulla pulled his starters early in the fourth and they made a little run, but it wasn’t enough.  Here are four reasons they lost Their offense was awful  The Sixers took 10 more shots than the Celtics through three quarters, mostly because the Celtics turned it over 12 times and allowed four more offensive rebounds. The Sixers had 82 points going into the fourth but were shooting below 44%.…