we must bear responsibility to bring things back to the balance they were at before we got there
The idea that nature was in some sort of balance before humans came along is a common misconception. Most ecosystems are dynamic, and change over time. What we are doing is accelerating that change to a dangerous level.
This might seem like an academic distinction, but many conservationists have caused more harm than good by trying to ‘freeze’ ecosystems at a state that existed at some fixed point in the past. I believe it was George Monbiot who pointed out that the margins of many British roads had higher plant and insect diversity than many ‘protected’ areas.
Friend, cool it with the pedagogy. If one understands the idea of ecosystems at multiple scales, it follows implicitly that one understands the systems are inherently dynamic.
The point still stands: we’ve got to understand the environs we’ve rapidly destabilized and do something to limit our negative influence. Ergo: keeping stupid cats indoors helps the stressed systems by reducing the load caused by a bored apex predator.
Oops I forgot my point in saying all that, which was that if cats have become naturalised to your local ecosystem, then removing them could make things worse. (And by the way, cats are not apex predators.)
By the way, actually, an apex is also known as the summit or peak of a curve, which domestic cats can generally be considered as they are rarely (though not never) predated upon. Wasn’t clear that you understood that, but now you do!