It also took quite a while for people to come up with the concept of universal human rights, we're still bad at overcoming tribalism, and basing morality on majority vote isn't necessarily the best idea.

That aside, you're right that I also do not assign equal moral standing to humans and nonhumans. However, that does not mean that the same arguments that make me reject culling humans don't also apply to other animals to some degree. I would argue the ethically most defensible approach would be nonlethal fertility regulation.

>basing morality on majority vote isn't necessarily the best idea

It isn't an idea; it's a reality. Establishing any sort of standard for moral behavior is necessarily an exercise in consensus-building.

And change in that consensus can only driven by those who reject it.