Because they don’t have the guts!
I’ve got a real bone to pick with this joke.
But you know they’ve got so many bones to pick with each other.
Anyway they can only achieve a hollow win
Seriously though, you come across them in a dungeon and they all attack you. Like why aren’t they attacking each other?
They’re not attacking you. They’re offering to clean your skeleton from all the inconvenient things like the meat and innards. Liberate your skeleton
Join us brother!
Nice, no meat on that joke
No that’s the intestines monsters. Now they’ll fight each other. Skeletons will fight them for the guts too. Skeletons LOVE guts and fight anyone for them especially each other, but they are notoriously bad at keeping them, since they don’t have musculature or skin to hold the guts in. That’s why they don’t have the guts and the context for this joke.
Neat fact - everyone has a skeleton inside them, well, unless you’re propelled entirely by magic like skeletons are