The group members all pledge to sacrifice themselves to Purgers so that other innocent people aren’t targeted, which is a wildly different idea for a cult, even if the show can’t completely unravel the philosophical logistics.
Beyond those more sporadic elements, The Purge TV show also gets dive deeper into the societal and political changes that come with being a dozen years into the Purge era, obviously from a genre-centric perspective.
The show really takes things up a notch a few episodes in.
USA’s The Purge also puts more thought into the concept of Purge-free zones, and the kinds of people who would end up there, along with plenty of other curiosities big and small.