The problem is not that leopards (or other big cats) are already extinct, but rather that their numbers have dwindled at an unsustainable rate.
Compare the population of big cats just 100 years ago to current time. These cats have been around for many millenniums at stable population numbers. Current numbers are smaller by orders of magnitude. Without these carnivores expect overpopulation of herbivores who can denude forests in excess numbers.
So it is not a stretch to posit that the carnivores are contributing to climate stability.
big cars in general and leopards are not in the same position. Leopards are certainly not unsustainable. They are very plentiful and do quite well close to civilization. I’ve seen plenty of them with my own eyes, I don’t have to read about it!
Lions are another story, they don’t do so well around humans.
In one area where I hunted in Namibia, cheetahs were prolific, they were hunted by anyone that wanted to from Europe, the US wouldn’t let them be imported. As my PH said, the US decided that they are endangered, so US hunters can’t kill them, so we book guys from Germany and Spain to hunt them. Makes perfect sense.