>>50128924
The Human spirits in the Animal Realm aren't required for the Animal spirits to live though, the whole comparison falls flat on that.
The Humans and Youkai reached a mutually beneficial agreement to create the Hakurei Barrier and seal Gensokyo from the outside world.
The numerous factions fighting over control of the Human Village is very similar to how IRL governments try and influence and control cultural centres, but in this case all factions mutually agree to work in Gensokyo's best interests (though with a slight tilt their side for their own benefit). Whereas IRL this is not the case.
Akyuu, at the end of FS, said it best: Youkai, as a whole, aren't a single monolithic faction so they will fuck each other over to gain control and influence over the Human Village. The Humans ultimately have the final say in who wins. Therefore, as long as you are human, you can get away with anything.