> Some people feel cheated when medication allows others to "effortlessly" join this social club, and then become vile and hateful in response.

I don't think this is just about a social club. Battling weight loss and habits is foundational to the human experience from the most recent centuries. Be it drugs, or anything else really that changes the nature of these challenges, people are going to feel discomfort because it's an attack on their understanding of the world, and in some ways, their beliefs.