(Legally, I think anything that isn't a protected characteristic is fine - you could legally say you wanted people to be Star Wars fans, believe in astrology etc, unless it could be shown that you were indirectly discriminating against people with certain protected characteristics.)
But indirect discrimination spreads the net wide:
Star Wars fans - predominantly men (probably)
Astrology fans - predominantly women (probably) etc
That's why it's dangerous to deviate from the EA-recognised protected characteristics.
For this ad, there's no problem for them to evidence that actual women are under-represented so they can encourage (actual) women applicants, as long as they don't discriminate against men.
But where is the evidence that other people who may identify as women are under-represented? They probably only have around 20 senior managers at this level. Even if trans people are 1:100 of the population, as SW claim, you're still not going to be able to demonstrate under-representation in a pool of 20. And, unless they have a trans man senior manager, why are they soliciting applications from TW, but not TM?