[asdfasgasdgasdg]

Perhaps not under your preferred moral system. But yours is not the only moral system. It should be obvious that there are plenty of moral systems where counterfactuals do indeed affect the morality of actions (e.g. any utilitarian system or compound system with a utilitarian component).

[sweetheart]

What moral belief system posits that it is moral to do something simply because someone else would do it?

Does anyone actual subscribe to such a belief? Do you?

[asdfasgasdgasdg]

I think you're reading me more broadly than I meant you to. As I mentioned in my comment, at a minimum, any utilitarian system would consider an action's morality in light of what would happen in the absence of that action. Yes, people absolutely do subscribe to utilitarian systems, at least as a component of their overall moral stance.

There are also of course many moral systems that do not value the welfare of other species as highly as that of humans.