I feel like maybe you missed the point? The concept of the Purge movies is the government is using the Purge as a smoke screen to eliminate the people it considers undesirable. It's supposed to be like Kristallnacht with plausible deniability.
What I think everdrive is saying is that for it to be a smokescreen, there needs to be smoke: if it was only the government participating in the Purge to eliminate undesireables, it'd be extremely obvious and rallied against. But it's not, regular people are engaging with it in droves, which is what they believe to be the unrealistic part.
What I think everdrive is saying is that for it to be a smokescreen, there needs to be smoke: if it was only the government participating in the Purge to eliminate undesireables, it'd be extremely obvious and rallied against. But it's not, regular people are engaging with it in droves, which is what they believe to be the unrealistic part.