Where is Bart going to hear the archaic definition of a word like that? And he wouldn’t be upset at free food - he’s no Homer, but he can be a glutton himself. Sorry, treis, but you’re overthinking this. He’s worried they’re going to put him in diapers. This is the Bart who confuses stoats with corn. [Okay, okay, that’s many seasons later.]
The Simpsons is full of jokes where a character knows something they shouldn’t.
Yeah, it’s from the old Norse.
And this could one of those times but for the inconvenient and troublesome fact that it’s not funny that way.
Lisa’s vocabulary is better than Bart’s, but her word choice is not always perfect (she’s only 8, after all). She once described Krusty’s third nipple as superfluous , when she should have called it supernumerary .
cause really, aren’t all nipples on men superfluous?
That was my thought, but I didn’t want to trigger an Intelligent Design debate.
They can be fun, though. Nipples, I mean.
Because “pampering” someone, in the sense of babying them or giving them special treatment, is a metaphor derived from the original sense of “Pampering” meaning to put Pampers on.
Okay, not really, but I can imagine a kid like Lisa thinking this.
You can? I just figured Lisa meant “pamper” as you described (“special treatment”) and the company that makes Pampers had a similar thought umpteen years ago and named their product accordingly. Bart, having a smaller vocabulary (though he is familiar with the works of Pablo Neruda), thought only of the diaper name and not the original verb.
C’mon, it’s Bart. Even when he isn’t, he wants to be thought of as cool. No way would he ever race to the front of the airplane if the prize was being put in diapers. Remember how mortified he was when his parents were looking at his baby pictures.
On the other hand, they’ve also hinted once or twice that he’s a lot nastier than he lets on, such as when he delights in the female panda (which is really Homer) being raped “Heh, you’re going nowhea sweetie”. Others may feel differently but one of the things that I love about the Simpsons is that the writers feel free to completely change someone’s character to suit whatever point they’re making at the time.
Hey, he’s honest about being ugly and hate-filled. 
That does fit with their habit of characters getting more extreme over the years. His relationships and feelings about women have also gotten pretty twisted. He’s a mess. Even his regular customers notice sometimes:
Homer: Geez Moe, you’ve been a real crank lately.
Moe: [pointing a shotgun at Homer] You take that back!
Homer: You’re always pointing that shotgun at us.
Lenny: And calling us dumbasses!
Carl: Which we’re so not.
It’s got its pluses and minuses. I think people get too hung up on the minor stuff sometimes, but I like a certain basic level of consistency in the characters.
Moe is a nice guy sometimes, but we can tell he obvious takes part in some of the more sinful pleasures in life, such as when he assumes Alice in Wonderland is a spoof of a porno called Alice in Underpants, rather than the other way around. Then there’s his Deer Hunter-style Russian roulette ring, his panda-smuggling ring, his killer whale-smuggling ring, and whatever other illegal rings he has.
And him being banned from the church, and all.
“Formerly Chuck’s” 
I’ve heard that it’s a reference to the somewhat jarring end of ‘Lord of the Flies’, where this naval officer shows up to interrupt the final confrontation between the kids and rescue them, a character that none of them had ever heard of before.
With a usual Simpsons twist a’course!