Those who have a preference for males of Arabic or Middle Eastern descent.
As a sexual preference, the term 'Arab' is more referring to males of Middle Eastern descent, rather than to the actual meaning of what is an Arab. There is no religious connotation to the preference, and is classed more of a Niche desire. Generally it is the 'bronzed' attributes that are being idolized, commonly associated with men from Mediterranean regions.
Modern use of the term 'Arab' is more about those living in an Arabic National State such as Iraq, Iran, as well as the religious connotation of being Muslim. However, the fact is that an 'Arab' is not factually someone who is simply a Muslim.
Modern history defines an 'Arab' based on their ability to trace their lineage back to the ancient Tribes of Arabia. Or to their first language being Arabic, or a variation of it. Or they live in a country where Arabic is the first language, or part of the official language of the Country. Any of these criteria are used to define who is, who isn't an Arab.
Whether a person is of Islamic Faith is not a criteria for whether a person is considered to be an Arab or not.