“Allowing his sacred rock to be nuked would prove to muslims that allah is a false god, and they would all convert to Christianity, Judaism, or atheism.”
We don’t react like that when somebody destroys a Cathedral.
The Rock is not a Cathedral. It is rather the most Earthly representation of allah - there is nothing like it in Christianity.
Muslims do not think like Christians, but rather in terms of absolutes dictated by allah - thus the phrase ‘if allah wills’ is a literal belief.
If a church or Cathedral is destroyed, Christians move on; If the Rock were destroyed: allah is destroyed and Islam stops.