If it had been anywhere other than a restaurant, I would have smiled politely and said, "Yes. Now, are there tomatoes or not?" Why make waves when one is a guest?
But this is a restaurant. The OP is ordering and presumably paying for a meal for his/her own enjoyment. Why the heck would anybody want to choke down something he/she doesn't like (never mind cannot tolerate, doesn't actually like) and be expected to pay for it?) It was a valid question asked--"Are there tomatoes?" It's incredibly dismissive of the server to respond, "Oh, like a kid?" No. Kids don't generally pay for their own meals to a business that deals in making tasty food for paying customers. (And kids aren't the ones who determine what a server is tipped. I smell Professional Darwinism here.)
My take would have been the Glacial Eye Of Death. I'm told that it can be felt from behind, according to my husband. And then I would simply have repeated the question. It's my food; I have the right of veto power if there's something in it that I don't like or don't want. I'm paying for it. The server's job is to take the order and serve the food, not to question my preferences, judgement, or indeed anything else.
(And yes, I have worked in the service industry. I would never have dreamed of making such a comment, even if I was convinced that said customer was being the ultimate Special Snowflake. The customer is paying for the meal. He/she calls the shots. It wasn't as if the OP was asking for special alterations to be made to the menu; just information requested as to the ingredients therein.)