You are just making that up. What “vast majority” are you referring to, exactly? The ones who carry epipens everywhere and keep their kids home from birthday parties? What exactly do they get out of that? What’s in it for them?
In my opinion, it’s a way for an otherwise unremarkable and uninteresting child to stand out. If you can’t be noticed for your abilities and what you can offer, then you can at least be noticed out of pity for being fragile.
But in any case, plese note:
http://www.medicalnewstoday.com/articles/185263.php
...along with about 8 billion other results for “peanut allergy misdiagnosis.”