I agree that the suffering of the innocent is wrong, but thats not why im a leftist. Maybe thats why this is so important to you and not as much me? Im a leftist because i like helping people and it gives me a justification to use that isnt religion. I do feel how you do about a specific type of suffering - I strongly hate anyone who pushes people to the margins of society and social situations, so ive always wanted to be friends with homeless people and trans people. If animals could suffer that way then id care more. The worst part about the animal holocaust is how alone and alienated they must be from a “happy life”. Their murder doesnt really phase me the same way starving people really dont. I also believe strongly in advocating for collective self interest because its effective. When you combine that with my love of authority and being dominated by people who deserve the authority it is why im a communist.

Not really related, but my time on a farm has actually given me a strong hatred of chickens. They kill eachother for fun, even when treated veey well with a coop thats too big for them. Cows and pigs are nice.