I think the idea is that his behavior was influenced by his "intake" of drugs, namely alcohol and pot. It's generally held that drugs cause people to do things they would normally not do. However, the people take the drugs of their own volition in the first place, so they take responsibility for what happens. You cannot blame the drugs and argue they made you do it.

So hey, maybe if the dumbass hadn't been drinking and smoking dope he might not have been teasing the animal. That pissed me off because I like big cats and it was put down because of his actions. It reminds me of a skit from Jackass. Kid deserves a darwin award.