They did block though, that's the point some people are making. The other team is composed of professional football players as well. The protection wasn't bad on that particular play and sometimes as a QB you have to give one of your teammates a chance to do something with the football. Graham catches that on the turn before the DB jumps up and he's got a chance to do so, MT could've possibly blocked for him as well in that scenario. Even after the DB jumps the route he breaks down 4-5 yards away from him, he was willing to give up that catch and you gotta just take that and maybe it becomes a 4th down that you can go for or again Graham muscles his way to a first.
Holding onto the ball in that situation was a bad decision. Carr did that at least a few times last week too. That doesn't mean that the o-line is absolved for their poor play just that there are things Carr can correct within his own play also.