Ok, sorry but I do not find the name Cohen offensive. And the reason you give for finding it offensive is a bit odd. Christian is a very popular boy's name, and the title of a huge group of religions. But you don't see Christians getting offended by it. Cohen is just associated to a sect of Jewish people anyway, its not like it is even a specific religions name.
Anywayyy....
As long as people aren't naming their kid a profanity or God or something similar I really don't find any names inappropriate, just silly.