He has less shots to deal with than pretty much any other keeper in the league. He's the keeper, it's not unreasonable to expect him to do a bit of goalkeeping every now and again, it is his job after all. Obviously in an ideal world we'd defend better and have no need for a keeper at all, but at the end of the day he is there to make saves. Like I said, it wasn't a howler by any stretch of the imagination, but in my opinion it's one that he could have saved if he'd got his positioning/balance right.
One way or another, we are letting in far too many goals for the amount of shots we let the other teams have. Obviously some of that is down to people walking it in after complete defensive meltdowns, but he's actually been remarkably good when everyone goes awol and it's him against the entire attack and has saved those more often than not. But regular shots from either outside the box or narrow angles are all flying in. Either we are just getting incredibly unlucky and every attacker is just picking out world class finishes every time, or Hart could be doing better. (I actually think it's more of the first thing than the second, as everyone's finishing seems far worse when watching games not involving us, but it's getting incredibly frustrating now that everything goes in)