Here we go again, unless they allergy person plans on sharing her sandwich , her eating it isn't going to hurt them. The announcement shouldn't be ALL peanut products, that is just going overboard and the main problem.
And this where we are going to continue to disagree. I do not agree that the only way a person can get hurt from a peanut butter sandwich is by eating it. Residue can remain and can hurt someone with a peanut allergy on a subsequent flight. This is a particular problem with peanuts because of the oil, and while I wouldn't advocate a ban on peanut products on ground, I don't think it is a good idea on an airplane that is isolated from medical care.
I hope you or a loved one never develop a life threatening food allergy. Our family has lived with this for over 7 years and it is not easy. I feel fortunate that my daughter is not allergic to peanuts, but she is extremely allergic to eggs to the point that casual contact on school equipment caused a severe reaction. Do you have any idea what it is like to get a call from your child's school principal to tell you that your daughter is saying her throat is closing up and that they are going to administer her epipen? She didn't knowingly injest anything with egg. She was just doing her math assignment at school and probably rubbed her face or put her hand in her mouth. EMT's were at her school within 5 minutes of having her epipen administered. That would not be the case if that happened on an airplane.
So even though my kids can safely eat peanut butter, you'd better believe we will happily refrain from doing so on a flight. I do feel that there is a risk, a minimal risk, but I'm not willing to take it.
I doubt I will make you see this issue any differently than you are choosing to see it, but as you can see, you won't be changing the way I view it either. I will continue to error on the side of caution with this. We will not die from not eating peanut butter for 2-3 hours.