Actually it is spot on and very practical. All of those examples you give are typically preceded by a strong 'dehumanization' phase, which allows us to overcome the inhibitions that we have ingrained against doing those things to humans.
Sure, but dehumanization is explicitly used to other specific out-groups of humans. Extending our understanding of sapience to other animals than humans would do the opposite of dehumanization. I don't think we'll see a future pan-sapientist Zimbabwe invade Botswana to liberate their zebras or anything like that. Empathy is generally easier as a tool for peace than war.
