I had a conversation like this about tuna fish once. No allergies, just people disgusted by tuna fish smell. Someone spouted off about how the inconsiderate coworker brought a tuna salad in and she had to go to the bathroom and puke and oh god it was disgusting and it should be banned.

It actually turned into a pretty interesting conversation. Luckily, only lunch, not life, was on the line, so it didn't turn into wank.