As a 54 yo FO they may not think that they will get enough "service life" out of you, irregardless how great you may be. (I don't know EK's retirement age, btw)
With your experience, why not go on a contract? There's plenty of contract gigs out there for guys like you-as captain, even.
And what is discrimination in one part of the world, is perfectly accepted in another! It's their playground, and their rules, not your likes!
Good luck, anyway.