> Abstaining from killing animals is about the sober realization that we can have perfectly healthy and happy lives without killing animals,

Maybe, maybe not. If one is lacking a hobby and happy to spend much time learning and obsessing and fiddling with what they eat, while accepting that they may be missing some vital things that we don't yet know about, then sure.

But I have enough hobbies and I don't want to risk missing some things we don't yet know about. I just eat what I evolved to eat.