Borris there have been fashion collections based on the aesthetics of Islam and Judaism just as there is plenty of art inspired by these faiths too. They are not just 'faiths' they are also culture. People can be Jewish and yet not part of the religion for example..... we acknowledge that... we acknowledge there is more to these faiths than just the belief system. And so they are routinely explored in fashion, art and film... not always in ridicule or criticism but often in an exploration of their cultural effect on people.
Its not necessarily insulting.
Catholicism has had a big effect on culture: art, literature, music, fashion and its interesting to explore that.
Im Catholic and most of my family are and they all just found it interesting... and perhaps more so than someone who wasnt Catholic because some of the outfits were quite subtle in what they referenced. Granted Rhiannas was a bit ott but I dont consider it an insult just a lack of imagination.