Murder is strictly defined as a human illegally and intentionally taking the life of another human. Even a human taking the life of another human is not always murder; we have terms like manslaughter (voluntary or involuntary) and other terms that we use when killing the victim was not the intent, and we also differentiate between premeditated murder and crimes of passion as well. It's also not murder when a soldier kills an enemy soldier in wartime.

But ultimately, it comes down to the first line- murder is strictly defined as a human illegally and intentionally taking the life of another human. As noted, not all cases of humans killing humans are murder. Exactly zero cases of humans taking the lives of non-humans are murder, by the very definition of the word.

I understand the emotional zeal that is felt by those who consider killing animals to be abhorrent- I really do. But making claims like 'meat is murder' doesn't help your case at all- if you're hoping to sway meateaters, painting a portrait of them alongside some of the worst criminals of mankind doesn't help anybody- it's abusive and puts them on the defensive.

Less offensive terminology used against minorities have been considered hate crimes. Think on that before you start throwing labels around. If you're really hoping for change, being militant about it is only going to enforce the 'crazy vegan' stereotype that is already out there. Better to attempt to garner compassion than try the route of personal attacks.