No, it isn't. You can try to win without throwing a horrible pass to a WR with no less than 6 Pats within 3 yards of him. It was a horrible decision that a veteran of his experience shouldn't make. He snatched a loss from what was, at worst, an OT game.
Ben deserves the criticism. It was a stupid play that a QB with his experience shouldn't make. But, he's gotten away with that kind of mistake before.
Last year (I think it was last year), when the Steelers played the Ravens, they won the game when Ben threw a slant to AB, short of the endzone, and Brown was stopped by 2 (or 3) Ravens. Brown made a heroic effort to extend the ball over the GL (and barely made it) for the win. But, if he hadn't broken the plane, time would have likely run out & the Steelers would have missed their opportunity at a game-tying FG. Ben got a "pass," because Brown made it work out. In that situation, with no time-outs, so little time left, & a FG to tie, passes have to be to the sideline, in the endzone, or uncatchable. But Ben went to his guy for the glory play, and his guy bailed him out.
Last night wasn't much different. FG will tie, no time-outs, little time left. The pass has to be a fade or an out, where only a Steeler or no one can catch it. Ben went for the glory play again, and it burned him.
He deserves the blame. But, IMO, almost everything from this game (except for the score, Brown's injury, & Gronk) was good for the Steelers. They showed that they were willing/able to change their "D," they (IMO) outplayed NE for most of the game, and, assuming they make the AFC championship game without Brown, if Brown is back for a game at NE, I think they have a shot at winning that game.
Brown has 5 weeks to recover/rehab his calf tear. According to
this site, if it's a grade 2 tear (partial tearing of muscle fibers), full recovery takes between "4 to 8 weeks with good rehabilitation." I'd assume Pitt tries to give him the best rehab they can. If they hold him out until the AFCC, he could be back.