One of the main reasons that this "stoners
" will smoke anything logic holds any ground is that they generally tend to be more trusting individuals. Either that, or they are simply willing to use anything that will get them high (or something that could be mistaken for a high - you know, general brain damage). This could be because they are depressed and smoking is their coping mechanism. Sure, it is not always the case - but you most certainly can't differentiate.
How can you feel good about fooling people into hurting themselves just because you have nothing better to do with your time? (If you can't feel good about it, then why would you do it in the first place?)
Drug use isn't even the problem
in this case, the problem is people who take advantage of others while they are vulnerable.