I mean can't they just say, ok you can eat your fellow wyverns but when it comes to humans, you don't do that. They would prefer to be buried and be one with nature or something To each of our own.
This is what most people do not understand, particularly in this era of "inclusion". They
feel (NB: most of what your average person does, particularly in this era, is feel about things--not think) that coexistence entails everyone accepting everyone else's customs
as their own. Consequently, they also feel that coexistence means people living on top of one another--no separation whatsoever.
This is absurd on its face to anyone with a working mind, but mindlessness is popular today; emotions are
queen.
The right way to coexistence--peaceful, lasting coexistence--is for all peoples to acknowledge that there are other cultures of other peoples, with their own values and resultant customs; acknowledge--but that's all. No one
needs to accept anyone else's cultures as their own, especially since there are some cultures with customs that are of absolutely no positive value to a civilized (not to mention
moral) society. Even though that's the case, those people with such cultures have every right to maintain their culture
in their own lands. Nothing's stopping anyone from visiting the lands of others as long as they
respect the culture of the people living there, otherwise, they can just enjoy their own culture in their own territories; or they can avoid going to a territory with a culture incompatible with their values. THAT is actual coexistence; anything else will inevitably lead to conflict--and, likely and ultimately, genocide.
It's like A and B living in a neighborhood, in their own houses, but with different rules in their houses. A can visit B, but A must respect the rules of B's house; same goes for B--he must respect the rules of A's house when he goes to see A. At the end of the day, either returns to his home to enjoy the comforts of the rules therein. They leave with friendly spirits, ready to see each other again.