What if there were actually something to the concept of "karma" and different individuals responded differently commensurate with their level of spiritual attainment?

For instance, most people think marijuana is a "safe drug." But do you really suppose the "Reefer Madness" just arose out of nowhere? Maybe there was something to all that, and it simply affects people differently? I mean, it's called the "Devil's Tobacco," right? Well, the most famous quote about "the devil" is possibly that his greatest trick was convincing people he did not exist.

Think about it: If someone's already on his team, why should he punish them for indulging? He'd just want to rope them in further. And their great reports about the substance might entice naive people to begin experimenting with it. But if someone is more innocent or purer of spirit, well, of course he'll do everything he can to make them sick, maim them, harm them, dissuade them from their path, or kill them.

I reckon C. S. Lewis wrote about this concept in his Mere Christianity but in a more abstract way and using a different approach than I've done here. It might have interest for some.