it is getting alittle old with hating beastmen.
I mean you're not wrong, but it's not hard to see how it would be a point of friction when when multiple races, species, and or religions all compete for the same resources.
True in an ideal society everyone would work twords the greater good, but it's never that simple. In any community its not uncommon for greed set in or for individuals to start seeking power or control over those around them. Yesterday's friend, becomes today's competition, and tomorrow's rival.
Hells, two farmers selling the same crops, in neighboring market stalls, is just a bad day away from become bitter enemies. It becomes infinitely worse if one is from a minority group, or from differing religions.
So it's easy to see why authors use such plot devices as a central theme in their stories. It's such a common occurrence that even we, the modern inhabitants of Earth, still struggle with it.