Leaving the animal example to one side for a moment and returning to the style of argument addressed in the OP - there is a class of moral argument that is legitimately vulnerable to the criticism that it has taken the consequences of a logical “axiom” too far, for example by treating the axiom as absolute without any possibility of qualification. The legitimate criticism is that the moral argument is hopelessly idealistic or unrealistic.
If I say that the primary moral obligation is to do no harm to others, then I can conclude that “Like, we shouldn’t be putting people in prison, man, because that’s, like, so mean. Putting them in prison can’t undo what they’ve done, and we should be all about forgiveness, man (insert rattling of love beads and swishing of kaftans here)”.
It is a perfectly legitimate moral counter-argument to reality test such a position. You can construct the reality test in a number of ways, no doubt (such as by saying the consequence of the position taken would be greater net harm to others than would be the case in imprisoning offenders) but all these arguments can be expressed in the shorthand form - that ain’t the way the world is.
Any moral position that blithely assumes the solution of intractable real world problems is legitimately criticised as - pointless. That is a valid criticism in its own right, and in addition pointlessness is at least a very strong clue that something has gone awry in the logical process that led to that position. It may be tremendously interesting to derive an argument from first principles to the conclusion that “war should be banned”, but when one reality tests this by reflecting upon just how such a ban would be enforced (by war, in the ultimate case) it is apparent that such a moral position is without merit because it leads nowhere. (Not that war is a good thing - just that the concept of a “ban” of war is sterile.)
Moral precepts are not like mathematical ones. In maths, it is perfectly cromulent to manipulate objects (like the square root of negative one) which have no correlate in the real world, and generate conclusions that are valid within the framework under discussion notwithstanding a complete disconnect with the material universe. While it is possible as a matter of form to construct similar moral arguments that do not connect to the real world, such arguments (unlike mathematical ones) are subject to the legitimate criticisms that they are “idealistic” or unrealistic or irrelevant.
Or in other words, reality is a legitimate player in moral discussions.
Or in other other words, to assert, as the OP appears to do, that the way the world is is morally unimportant is mistaken.