He was the puppet master encouraging Dallas to use enormous amounts. I’m sure he was alsobmaking some hefty promises. I also have no doubt he was supplying Dallas.
So, then your logic can apply to any criminal who is encouraged by others to commit a crime? Murderers? Bank robbers?
I mean, if person X robs a bank, but was influenced by a "puppet master," person X is less responsible for their actions?
Are you only going to apply your logic to bodybuilders who use drugs? Or, to other people as well?