User blog comment:Kaido King of the Beasts/Chapter 763: Another Backstory, Another D, and Another Great Chapter/@comment-4493594-20141008195306/@comment-24638955-20141008212346

I think that if we give a more in depth thought more than Doffy's fault was the education he recieved from the school in Mariejoas or other tenryubitos influences that made him do the wrong actions that led to that.

Because kids just imitate what they see and learn.