Why doesn't the government in the world of comic books kidnap and

experiment on superhumans and murder them??

There are comic books where the governments do experiment on humans and super humans. Governments can also execute super humans who break the law.

@Harryman said:

experiment on superhumans and murder them??

Huh? They do all the time. This is really prominent in the X-Men books.

1 word... Cadmus....

Another 3 words... Operation Zero Tolerance....

I could go on.