We shouldn't even struggle for people who don't struggle themselves, let alone struggle for animals, or fungi, lichens, or other forms of life.
We struggle among those who struggle against power, wealth, oppression, exploitation. I am not going to turn against a hunting and gathering forest community because some metaphysical ideal of separation of dna forms. Between the rich vegan and the poor hunter/fisherman, I'm on the side of the hunter/fisherman. Between the pent-house tofu eating bastards and the earth's near half of the population living in coastal and river areas of the entire "developing" world and barely surviving, I choose the later.
Tell this to millions among millions of Bangladesh vegetarians and farmers, pushed off the fertile land by police/army serving western multinational grain/fruit corporations, and chased to coastal swamps to survive on fish and roots of amphibious plants.