(1) Bowing the head in front of Mazaar is unislamic if it is equal to Ruku (part of Namaz) and those who are doing like this are non mulims and if some muslims are doing this action than either he is unaware of Islamic Law or he should perform Tauba.
(2) All muslim in the world belive "Kaaba" as Holy House of Allah and is Symbole made a center for entire world to perform Namaaz. and Dear we do respect the Holy land of Makkah and Madina and not worship the same than forget about Place of India.
Entire land of the world are great and to be respected because the eintire world has created by Allah.