And since superhumans seem to get powers randomly, there's a good chance they end up with another Homelander/Soldier Boy/Queen Maeve/Bombsight/Ryan/whatever who is super strong and close to indestructible that will be impossible to kill or control. That doesn't even get into the other dangerous types like Victoria Newman or Cipher who, though mortal, can do shit like take over other people's bodies or make their heads explode.
Butcher is correct at the end of the series: superhumans will continue to be a problem. But of course, this is libshit storytelling so they have to swerve and he takes the most extreme solution possible to act as a strawman for why the neoliberal status quo must continue. Any systemic or radical change must be avoided because it implies liberal institutions have no legitimacy otherwise, as they are unable to deal with existential problems.