I sympathise with those who genuinely have a severe nut allergy which can be triggered by airborne particulates.
It is much more common now. Barely a week goes by now without at least one flight being nut free.
I side with the airlines. Most make it clear that they cannot guarantee a nut free environment. Airlines can ask people to stop eating nuts but what about the previous 600 people who had been on that aircraft and now on sector 4 who can say there are no traces of nuts in the furnishings? What about the 200 passengers who purchased nut products on the aircraft? Who can guarantee that the guy next to you didn't just devour a large bag of peanut M&Ms just prior to boarding. What of those who don't speak the language in which the 'no peanuts' PA was made? If the risk is so severe, then you shouldn't be travelling.
I don't mean to sound unsympathetic. But if it's so bad, wear a surgical mask and gloves. I see plenty of people these days doing that. It just another example of the majority having to change their way to accommodate the tiny minority. An 'allergy' is almos a badge of honour it would seem to generation snowflake. I can see airlines removing and banning all nut products as a result of today's litigious society.