Thank you for writing this. Folks tend to find it very difficult to face mental health issues honestly when "bad decisions" are involved. It is hard to accept that people who have done terrible things may not have had worse morals or less self-control than ourselves--they may have actually been in a situation where the temptation was simply greater than they could manage. Every "normal" person has experienced the same thing, though typically with "bad decisions" that are of lesser consequence (e.g. eating poorly, minor deception, failing to follow through on things ...).
It is likely that having been in the position of someone who has done something terrible, living with similar stressors, having similar predispositions to certain temptations, etc., most of us would have done the same.
Our evolved social response is to condemn and judge, which clearly has served a valid survival purpose. But we can also develop the capacity to understand the judgement response from a more objective perspective and look beyond it.