You are correct, the earth will soldier on after we are gone, probably. But why make it and ourselves suffer in the meantime? That's like giving someone a routine surgery and not giving them pain meds. Why? Cause they will survive without, so why bother? It's the easy way out that requires the least amount of effort and has the maximum consequences, which in our case would be extinction.
And yes hunting is cruel and unnecessary, you don't NEED that meat, so why go out and kill it? There's plenty at the supermarket? And in terms of digesting meat, it doesnt matter if its wild or factory bred, our intestines aren't good at digesting it. Look at a carnivors digestive track, its shorter than ours and has much more concentrated stomach acid. My argument isn't if we can or can't physically eat meat, but whether if we should?