While Anya has personally witnessed several major wars (and even managed to indirectly start a few or make them much worse than they otherwise would have been) she’s often very hazy on what people thought they were fighting for. Willow is horrified when Anya reveals that she has no idea what the War of 1812 was even about, even though she lived through the whole thing. Anya shrugs and replies that she never really paid attention to politics when she was a demon, since none of it really affected her.
On the other hand, Anya is very sympathetic when someone explains the American War for Independence to her. Of COURSE the Americans were willing to fight the government in order to avoid being taxed. She’d probably do the same if some faraway government demanded her hard-earned money. Giles points out that the current government DOES expect a portion of her paycheck, and it takes fifteen minutes for her to stop going on about the injustice of it all.