First, I addressed the issue of the contrast between his sexual preferences and his general lack of self-control in my prior post.
Second, yes, there is a ton of research that has shown that certain types of crime (pedophilia, rape, animal abuse) are heavily and statistically impacted by physical or psychological trauma. Again, there is not an EXCUSE there, but an attempt to understand what causes the aberrant behavior.
In addition, it would help to factor in whether "punishment" (i.e., jail time) would have any impact on changing the behavior in such an individual. Sure, it is possible for one who commits theft to be "rehabilitated" from incarceration, but we have to honestly consider whether jail time will ever change a pedophile, a rapist, or an animal abuser.
Again, please differentiate between the concept of "excusing" a person from a crime and an honest discussion of what influences someone to commit a particular type of crime, and whether they will ever be rehabilitated from committing that type of crime again.
If Kellen is convicted of the crimes of which he is accused, he probably needs to be locked up just to protect other people, but being in jail will probably never address what is wrong with him in a way that rehabilitates him.