With Sylvanas raising Blood Elves and Night Elves as Dark Rangers, it gives both factions access to the class.
The first one, Night Elf Dark Rangers and Dark Wardens. Why class an not allied race? Well, Blizzard left a couple little clues around. I am guessing, and it is all for fun, but next expansion we will see a Dark Ranger type of class. Maybe not so much to grind for them but that is not the focus here lol. I did not expect allied races, but the moose tauren and upright trolls made me wonder why. Back in Legion, when I noticed the upright trolls I had a guess that we would get customization soon.