But you are arguing that it is wrong
. I mean you just wrote: "but if it becomes a mandatory criterium something in your mind is going horribly wrong"
And I will repeat again that it can never become a mandatory criterium as everybody has the equal right and possibility to make a group based on whatever criteria that person wants.
It is 100% a you-problem if you apply to a key which key-holder is using criteria that you don't like.
You have 100% the exact same rights/possibilities as that person to make your own group and pick people on the criteria that you find right.
If someone refuses to take charge of their own in-game experience and that someone 100% relies on being led by other people then that someone gets the experience he gets, but if that someone would man up and take charge of his own in-game experience and start to lead then that someone and maybe others like himself would get a completely different in-game experience.
Blizzard has since day 1 of WoW given the players 100% free reins in how they make their groups and whom they play with. Nothing has changed in that regard. Some people use that freedom to shape their in-game experience, others don't.