Alas, you’re correct - I have never (even when I was Catholic) seen any basis for supposing that other animals are not endowed with a soul. In fact, I recall saying to my mother once that I would not like to go to any heaven that excluded our dog…and my Mum agreed.
I still need something other than anthropocentrism to justify the notion that humans can do whatever they like to other animals and not really care. And by this I mean more than the Biblical prescription that humans have dominion over the earth. There are two possible interpretations of this: one is that we are stewards of creation, and therefore obliged to take care of it with the same consideration we show to our own kind; the other is that we can use and abuse nature at will, so long as it serves human purposes - and that is easily dismissed as arrogance, and wilful ignorance of consequences that we are already seeing all around us.
Finally, I don’t understand how it is favourable for the human population to keep expanding when it is abundantly clear that the earth cannot support all of us in any tolerable level of comfort. Some have faith in those who are engaged in technological research, but surely that is expecting too much of others when we cannot at least attempte to remedy the problems on our own behalf.
As usual, it is hard to point to any specific problem when all problems are interrelated, and the greatest of them all - human overpopulation - is ignored by those who continue to believe that unfettered human expansion is the ideal.