The way I read the situation is that this cashier has poor social skills and has been told to ask the customers questions, in a lot of stores they are pushing cashiers to ask about the meal their cooking so they can suggest related products or find out if they were looking for anything and couldnt find it.

That can be difficult to navigate at the best of times but if someone has poor social skills and the instructions were vague you end up with situations like this.

I've worked with cashiers who have had autism and some asked questions like this and had no idea they were being insulting.

I worked in a small location and was able to obverse what was happening and provide support and training and the cashier did improve.

In big locations that's a lot harder to do because you have more staff and more tasks to monitor so its just not getting picked up.

If your this worked up over it, talk to a manager so they can step in and help resolve the situation.

The cashier was in the wrong but its not necessarily their fault, OP thinks that hes being attacked and it was done with malice (in other comments he's mentioned having similar reactions to other insignificant comments).

OP's comment shut the conversation down and solves the problem in that instance for him but its still an asshole move.

I feel like I phrased the bit about it being a sensitive subject poorly but he's in a public place, in a context thats supposed to be family friendly. Its absolutely 100% inappropriate for him to make a sexual comment, even it was quite light.

Not that it actually matters but OP didn't give us a description of the cashier, for all we know this is a little old lady, a teenager on their first job, someone who's devotedly religious.

Some people would take the comment fine, others would be politely offended.

OP is the asshole in the situation because there were better, more mature ways he could have handled it.

ESH is as generous as I'll get though I'm leaning way more to YTA.