Do you also consider it murder when fast animals with sharp teeth and claws attack, kill and eat slower, defenseless animals? I call that "nature," not "murder."
Humans can't fly. They're not that fast. They can't swim underwater for long periods of time. So they have to obtain food using the best weapon nature gave them -- their brains.
You obviously have no problem with people raising defenseless animals and using technology to kill them for you to eat. But for some reason, you feel morally superior because you pay mercenaries to do the dirty work for you. How convenient.