To Orthodox Jews,
Cohen refers to a sacred bloodline said to descend from the biblical
Aaron. Cohens have special privileges, but they also have restrictions (e.g. not marrying a widow, a divorcée, or a non-Jew). These restrictions, according to the Jewish faith, maintain the "pureness" of the bloodline.
Some Jews aren't offended by it. They feel naming your child
Cohen, regardless of faith or faithlessness, is better than giving your child a name that is little more than a meaningless string of popular sounds. On the other hand, some Jews are extremely offended and find the use of the name by non-Jews to be ignorant and disrespectful. To them, the name is more than simply "priest", it is a religious statement.
Cohen is a holy name that deserves to be venerated, in their opinion.