I don't understand why Yrel is painted in such a bad light by players. The sole PoV we've got about her and her forces is from Orcs who :
-slaughtered Saberons and Botani almost to the last, at least in Gorgron
-have been led for decades by the warmonger who created the Iron Horde
-enslaved Ogres and Gronns for decades - and yes, the former did the same to orcs and the latter are mostly brutes, but they all are intelligent beings
-use a variant of Goblin technology, which isn't known for its environement-friendly nature
We also know that the Lightbound resorted to violence when they had no other choice and still preached peacefully even at the eve of their final battle with the Mag'har orcs.
Is converting all cultures into your own, using force if need be, a good thing ? Of course not. But unlike the Old Horde, which attempted to kill all Draenei, the Iron Horde which extended this goal to all inahbitants of Draenor and Azeroth, and obviously the New Horde under Garrosh and Sylvanas, whose most atrocious actions are well known, the Lightbound are not out there to kill everyone.
They even allow converts to achieve positions of power, as with Exarch Hellscream, implying that they do see everyone as their equals once they have chosen to join them.
Even if they end as enemies, they shouldn't be irredeemable monsters just there to prove that Geya'rah is justified in her blind hatred of draenei.