Maximo's case was different from what is transpiring now. First, Maximo was battling a zombie with his life on the line. Second, Maximo had pleaded for his help. Third, is that Nile knew that carabaos are not harmful, at least, before the apocalypse.
The three mutated animals were fighting because of their greed. Although it was their nature, Nile did not see himself as the saviour of everyone else.
Besides, they are already considered as dangerous animals even before they have mutated due to the apocalypse.
...
Nile approaches the body of the dead mutated lion. He draws out the Katana and starts to shave off the mane of the mutated lion. Its mane was the one that got mutated. Although Nile did not know what use this mane would bring him, he still decided to store it inside the storage space, the storage space had a lot of space for now, anyway.
Nile thought that the mutated parts of the animals might be useful in the future.
Thanks for the gift
Lunalrys