Is calling someone a “Poopy Head” offensive? [closed]

Recently I followed a meta discussion where one called another who was complaining about lots of different things a "ranting Poopy Head" and I was asking myself if that comment should be flagged as rude or offensive. English is not my native language. When I googled, there were unclear definitions like this in urban dictionary:

The single most offensive thing you can call someone. It's like the atom bomb of arguments...

So I had a look into Google images, where pictures like the following showed up:

I'm still ambiguous about the meaning. Is it meant belittled in a friendly way or is it indeed rude and offensive or does it depend on the context of the situation it grew out?

It is a hair offensive, but is the sort of epithet that might be used in a joking manner.

Certainly there are far ruder things one might say -- the person who wrote that was, at the very least, attempting to choose as mild an insult as possible.

It's a children's insult, used by adults only ironically or in an effort to be deliberately childish.

It would be considered a very serious and offensive insult among children, so when used by an adult, it combines hostility with playful self-mockery --a way to say something offensive with little danger that anyone will actually be offended (it wouldn't be possible to respond without admitting to comparable childishness).

It's comparable in register to saying "she's got cooties!".

It's also very North American. To outsiders, it appears to belong to that class of childish US euphemisms that include "hiny", "buns" and perhaps, "cooties". Cringe-worthy when coming from adults. As a euphemism, it's probably an attempt to avoid the offensiveness tag you want to apply, but ends up being worse than a cruder term for other reasons.