Most world leaders also don’t call the Armenian genocide, genocide despite the fact the word was coined to describe it, and you have plenty of examples of genocide after WW2 that were tolerated by the international community. International politics are not a good court, because governments by their own nature tend to focus on what’s expedient for the national interests and not in what’s right.
Edit: I just remembered a particularly nasty one, remember when the western world and China decided to support the Khmer Rouge and the Cambodian Genocide (and before you go full denialist on this one, it was classified as such by an international court).