I can't even believe I have to say this, but NO, Superman would not be okay with the government asking him to become an executioner...
And how would he kill them exactly?
Beat their skulls in with his fists? Choke the life out of them with his bare hands? Burn their flesh with his heat vision?
Why are we even talking about this!
Just accept that this is the direction they have taken.
Then, you can either decide this version isn't for you and stop watching. OR you can decide to enjoy it for what it is - an elseworlds tale.
'In Elseworlds, super-heroes are taken from their usual settings and put into strange times and places - some that have existed, and others that can't, couldn't or shouldn't exist. The result is stories that make characters who are as familiar as yesterday seem as fresh as tomorrow.'