Exactly.
I'd like to answer you because I'm one of those who wrote that, but yes, in fact it's exactly as if the author wanted to find an excuse/justification for his behavior, I think it's clear... It's as if she wanted to tell you: he's not like that because he was born a psychopath or a narcissist, he's like that because he has past trauma...
I have a feeling that the moment Dan starts loving again and JJ opens up, we'll all be thinking like Doc. One moment we love him, the next we hate him, and the next we wonder why this keeps repeating itself.
I think what alot of people are missing isn’t that the backstory is a excuse for his behavior, but it is the reason why be is behaving the way he is. You don’t have to forgive him for anything he has done, but I think it is to understand why he is the way he is.