Most major airlines have a max. age for hiring FO`s, some even have a minimum and maximum height of the applicant, some airlines still refuse to employ female pilots.
Many airlines also do not inform the applicant why he/she was not successful.
Telling an Arabic airline reqruitment department you are dissatisfied with their policies on reqruitment, will get you a blank stare and a shoulder shrug, and it will not change the fact of you not getting hired.
The fact that you are obviously experienced, and well qualified, does not nessecerily land you a job. These days Airlines can pick and choose among vast numbers of applicants, most of them well qualified.
I hope you get a job soon, but do not feel they owe you the job when you do the interview.
Good luck
