Christian culture is superior

A Moslem congressman wants to ban a prominent Dutch poltician because:

Mr. Wilders’ policy agenda is centered on the principle that Christian culture is superior to other cultures.

I thought that most Christians believe that Christian culture is superior. If they thought that Islamic or Confucian culture were superior, then maybe they would convert.

Maybe Moslems do not understand this, as many of them are born into Islam and are not permitted to convert out.