Perhaps there aren't enough in the current group of flight attendants to serve what will be an increasing number of Arabic customers as a result of the EK/QF alliance.
EK Flight Attendants don't need to speak Arabic. The only requirement is fluent English.
One would argue, why would you offer redundancies to French, German or Italian speaking QF Flight Attendants when AJ's plan is to fly these punters to/from Dubai/Australia legs on Qantas metal to connect with EK's network to Europe.