How come muslims don't let non-muslims go to holy places like the Dome of Rock or Mecca?

I find it so unfair that christians allow muslims to vist our churchs and holy places.We Christians even let Muslims build there Mosques in our holy lands(ex. near Vatican City) ! We Christians even acknowledge Muslims as citizens of our countries yet Muslims never allow Christians to build there churchs in there holy lands(ex.Mecca) and only a few Muslim countries actually acknowledge Christians as citizens(ex.Lebanon,Syria,Egypt..). Why are Muslims so defensive about Christians and other Religions visting there Holy Places?