Ron: "It is hypocritical to say that you are for animal rights, saving ecosystems and perpetuating species, and then allow free-roaming cats."

"Ecosystems," that's the key.   It sounds like there are areas where the feral (or outdoor) cat population has gotten too large for the preservation of some diminishing species of birds or other small animals.   But without predation by cats, avian raptors, etc., the population of pigeons, rats, mice, etc., and get out of hand too.

Here in the Pacific Northwest, we've celebrated bringing the Peregrine falcon back from the brink of extinction, though this raptor will take its toll on the populations of many other species.    Similarly, with wolves removed from so much of the US, the deer population tends to grow too large and many deer end up perishing from starvation (not to mention playing chicken with automobiles).   Sometimes the predators provide a valuable function in stabilizing the numbers of their prey.   When the prey become a threatened species, the predators become a problem and their numbers need to be curtailed.

It is not always a negative thing when cats prey on birds, lizards, rodents, etc.