>>212979871It never stated he was braindead.
It's like in the comics, where he does clone superman too, but not very often. He doesn't make an army of superman clones.
1. They might rebel against him and he already hates superman so why would he make more?
2 it's probably incredible costly
3 it's probably difficult and not an exact science or something
Cloning done in fiction isn't usually done to create an army for some reason, it's just not done very often except maybe in Star Wars with the storm troopers but then you have Palpatine making clones and yet he doesn't make very many