Well. I've been doing a bit of initial research on dart frogs and I was thinking of making my own vivarium for this summer, and I've come across a few threads about people who have been given/bought mixed frogs. Now, many people make it crystal clear to isolate them for they could breed and create 'hybrids'

So, my question is, what is so bad about hybrids?

*The only legit reason I've read so far was the hybrid could be born deformed and ill, subsequently dying shortly after birth.
** Seen a few arguments saying that hybrids are not what nature intended, feeble claim to be honest.
*** Seen others who say that hybrids look 'funky' and can never be sold.


So, is the hatred just ethical or is there a practical and legit reason why hybrids shouldn't exist?