In addition to what is said above in article:
Saudi Arabia is the richest Muslim country where there are no poor people to be exploited.
Saudi Arabia basically is an Arab country; foreigners will remain foreigners even they live hundred years. Each foreigner is counted for and all information is in the computer. There is no way if a foreigner commits crime and get away with it due to lack of information. No one gives protection to criminals, unlike in Pakistan.
The major resistance might have come from Palestinians like Hammas or other Jew resistance. But Saudi Arabia though an American ally, pays billions of dolloars in aid to Palestinians, so chances of any reaction from them is none.
Once a crime is established by Saudi official through short cuts, there is no way the person is not punished even he or she is innocent. For most of the crimes there is a capital punishment.
Population of Saudi Arabia is much less than Pakistan.
I think these are the major differences which make Saudi Arabia as safest Muslim land, though somtimes violating human rights.