They are. You can't get sacked 103 times and probably hit hard a hundred more and not have your footwork, technique and everything you do as a QB affected. Its impossible. Only people who never played a contact sport think that type of physical abuse, to that degree, shouldn't have an accumulated effect on your technique and psychologically. Its not about toughness either. Just the fact that he kept getting up and competing speaks to his physical and mental toughness. But its impossible to get hit as often and as hard as this kid did, often times before he could even complete his drop back and set his feet, and not have it effect your overall game. This level of abuse is what ruined Ken O'Brien and Bert Jones (who would be in the HOF if the Colts had invested in his protection) and many others. Thats actually my biggest concern with Hackenberg, not fixing his mechanics. I just hope he's not already shell-shocked and seeing ghosts.
It nearly ruined Jim Plunkett too, but the Raiders were able to restore his confidence, give his body time to heal, and he bounced back and won them two SB's, after most teams thought he was physically and mentally shot from the years of abuse he took in NE. Thats what I'm hoping we can do with Christian Hackenberg.