It's not really about the humor. It's always about the cruelty or, in this case, cruelty's sibling: mockery. To their twisted mindset, cruelty towards their perceived enemies is always funny and/or righteous.
Once I realized most Republicans only care about making the 'libtards' suffer, everything they do finally started to make sense.
They consistently vote against their own interests. They elect obvious cartoonish scumbags. They get outraged about nonexistent wars on Christmas. They think Democrats are cunning and powerful overlords controlling everything, but...Democrats are also (simultaneously, somehow) incompetent fools and suckers.
The cognitive dissonance is drowned out by their blind hatred. That's why they post social media replies like "seethe" because that's what they do, 24x7. They're seething crazy-angry all of the time. They can't go five minutes without thinking about politics or putting their right wing spin on every anodyne topic of conversation. They ban wholesome children's books. They actively strip away basic human rights while claiming to be victims of the same. They steal elections and break the rules of congress and the courts while calling the other side cheaters.
They are quite willing to see the planet's environment burn to the point of mass extinctions...as long as the 'libtards' suffer more.
Once you understand their "cruelty first" philosophy, and see them through this lens, their behavior becomes sadly predictable.