There was a post about making cats vegan. The mod then decided that people posting information on why that is a bad idea were antivegan or something. The mod started then removing any information that pointed to cats not being able to be health while on a vegan diet. The Lemmy.world admins them stepped in stating that improperly feeding your cat constitutes animal abuse and is unethical. This made many die hard vegans very mad.
For the record, cats can not be vegan. They can survive on it but they will have shorter more painful lives and they will go blind. There bodies start breaking down without the proteins and amino acids found in meat. I understand why vegans would be unhappy with that answer but it is the way it is.
Interesting enough, that's not the case for dog. You can put a dog on a vegan diet as long as you are very careful and are constantly monitoring. It isn't for the faint of heart and can have very sad outcomes. It isn't something you can arbitrarily do.