I’m not sure I’d necessarily blame humans. A hybrid between two species that are in different genera, which diverged over 6 million years ago, and which have different numbers of chromosomes, would likely have had any number of genetic abnormalities which could have caused it to die. “Hybrid vigour” only works up to a certain point, generally only within a species. Once hybridisation occurs outside the species, more health issues rather than less appears to be the norm.