A lot of people who think they know the game simply look at the pressure and assume it's all the OL's fault. They don't see the QB holding onto the ball too long, and think the five guys on the OL should be able to pick up 6 and 7 blitzers sent so often because the QB doesn't get rid of the ball quickly.
As you said, the OL needs to improve, but PT continues to put them behind the 8 ball with his own lack of development. The game is still too fast for PT. Opposing DCs recognize that and, as a result, their defensive gameplan is to make it even faster using stunts and blitzes. His accuracy is shoddy enough that they're willing to take the trade off of single coverage against dangerous receivers in order to increase the pressure on PT- with the belief that he won't make enough plays to win the game. The OL is constantly fighting an uphill battle because the guy behind them hasn't learned how to climb.
Guys on the OL are going to get beaten sometimes, they're going to miss some assignments and sometimes their gap is overloaded and they have to make a choice. The PT apologists are going to have to realize that he can't expect a perfect pocket on every play. He has to overcome some adversity as well, and help out his line by making a defense pay for blitzing. I'm still not seeing pre-snap reads, where he might be able to discern where the blitz is coming from and put the ball there. I never see him throw to his hot read. I just continue to see him wait until he's at the back of his drop before reading the defense, then getting flustered when he can't camp out in the pocket before finally making a questionable decision for which he is occasionally bailed out by a receiver. He now has 17 starts under his belt, but he looks no different than he did when he had 0. No matter how hard some may try, they can't blame the OL for that.