From other comments, it seems he wasn't tried for that stuff though. I don't think it's a good thing to include considerations in sentencing that he wasn't tried for. If there's evidence he did that, and you want to put him away for a long time because of it, then try him for it!
Punishing him for that without trying him for it seems like punishment without trial, which is bad. The alternative is that this punishment is just for nonviolent stuff, for which it seems excessive.