Fluency in Arabic
That page, if you read it, is specifically referring only to those applicants who are applying in person at the headquarters in Dubai. ALL applicants, no matter where they are applying, MUST speak ENGLISH, and that is the only compulsory language. Speaking ONLY English will be (in practice, but not officialy) a detriment to your considering the thousands of applicants they get that are multi-lingual, but you can still do it, and good luck!