The thing is though, how many times you eat meat you "caught, skinned, filleted, and stuck it in your freezer" the source? Even if you do it all the time, the average person doesn't do it 0.01% of the time. Which implies relying on the meat industry, and I already explained about that.
And what is it with bringing up thousands of years ago? Ever heard of evolution? Just because Neanderthals did something doesn't meant it's also "natural" to do for us. Neanderthals also lived in caves and wore skin. You might claim that vegetarians are the newbies (we are not), but that doesn't make our eating habits any less natural. Actually I believe humanity should have dropped eating meat centuries ago, about the same time they stopped burning people for witchcraft, but sadly humanity doesn't always evolve the way it should.
[And our great ancestors were mainly frugivores, just fyi.]