If for some reason I had a really religious pacifist friend, the nickname flow from Quaker Oats into Oatmeal seems like it would be a really realistic occurrence.

I don't see how these are supposed to be insulting. "Poopy-head", in all its infantile childishness, would at least be intimating some lack of hygiene.

"Those marshmallow minions over there, they're probably conspiring to have a nonviolent and safe barbecue with the community to foster community spirit! How evil!", see? It's just ridiculous sounding.