Because they're under the illusion all the impositions of civilization are unnatural constructs of oppression and once they're removed a paradisaical state of existence will be revealed. So if after tearing down that MLK Jr. statue, paradise isn't manifested, it must mean some other vestige of oppression is still lurking and must be hunted with even greater zeal. The death spiral they're trapped in is horrific. The living will envy the dead.