Whatever it is, it's none of his business. The cashier is disrespectful. Please try to find service at a different store.

You don't have to explain anything to anyone and screw them for saying something. Hope you feel relief soon.

They need to learn to mind there own damn business

Being that I understand, from a cashier's point of view. that normally yes we do mind our own business. but it can be mentally taxing to watch people buy items that many times it's obvious they're using them for the wrong reasons.(E.I. teenagers trying to lose weight, people that are obviously anorexic, or drug addicts buying laxatives to cut their drugs with) and it could simply been the cashier was just trying to care

"You know, that’s not a good way to keep your job". That would be the perfect response for those who are too nice to say "zip it, smartass".

This is when it's okay to be a Karen or Kevin

I find it very annoying when cashiers comment on what you purchase. It's not their job to provide commentary. Scan the stuff and shut up.