I knew someone who did die from a peanut allergy when I was in my 20's. I can understand how that is a frightening thing to deal with.
I was on a flight once were they announced they were not serving peanuts because someone on the plane had a severe allergy at which point a couple in the seats across from me did a high five as it was their child apparently. This did not do anything to help ambassador their cause and in fact did the exact opposite for me.
The OP doesn't deserve to be dumped on but at the same time shouldn't be campaigning to get others to leave as that is as effective to others as the high five was.
I would agree with others that if DL can't adequately protect you from peanuts then perhaps the cost of the ticket is less important than the airline you choose.