Yeh, you really run the risk of devaluing words if you use them at the drop of a hat. If everything is genocide then nothing is genocide. The boy who cried wolf. You've gotta have parameters to strictly define things and intent is important. But I'm still not convinced the Horde isn't interested in an ethnic cleansing of Kalimdor, or that the Alliance isn't likewise aspiring for one within the Eastern Kingdoms.
Yeah that's certainly the counter problem to denouncing a political faction. One eventually become so righteous, justified, zealous and vitriolic in their condemnation of "the oppressor" that they dehumanize them and see them as "the other" in the same fashion that "the oppressor" originally viewed their own victims; and when one can dehumanize another then violence becomes an option on the table, one thing leads to another, et voila, genocide.
The spirit of
viva la revolutión hinges contingently upon the revolution never actually being successful, and the institutional monolith of "The Man" remaining in power to be rebelled against - for if they are deposed then the revolutionaries are forced to seize power and assume duties of practical management which may put them at odds with their abstract idealistic theory until they become The Man themselves.
This whole thing is a horseshoe with its roots in evolutionary biology, human tribalism, subjective/arbitrary in-groups and out-groups embedded within our (and apparently the races of Warcraft's) nature. It's only
natural, but probably the most reprehensible part of human nature and any defense of it is certainly guilty of the naturalistic fallacy. This dehumanization and othering, as you said, of people for political ambition, or climbing the social dominance strata of victimhood after an atrocity (like Teldrassil) to justify further retaliation is stomach-turning. I have
a twelve page thread of Alliance almost unanimously saying no war crime is too reprehensible to visit upon the Horde.
It's reprehensible, but it makes for good story in an RPG because it forces us to wrestle with who we really are but perhaps should strive not to be.