It’s a stupid idea because it’s not workable. You could never kill them all, and even if you did, you can’t kill an idea. The Quran is already out there on the Internet, and it can never be got rid of. So even if you killed all the Muslims, some wackadoodle eventually would find the book and resurrect the religion.
It’s like herpes, it’s not curable and there’s little can be done apart treating the eruptions as they occur.
It would still be a blessed relief that it had to be resurrected from scratch.