This claim in no way justifies the allegation that meat eaters are murderers and in logic qualifies as an appeal to nature.
In science we are omnivorous homonids like wild chimps, who have also been observed fashioning weapons to kill and consume mammals. And if we were not meant to consume foods that we cannot consume as is then we should also not be consuming beans, bitter almonds and cashews because of our susceptibility to the their toxins.
The lectins found in uncooked beans are toxic to humans, as is the cyanide found in uncooked bitter almonds. And cashews are encased in a hard shell that contains urushiol, an acid that is known to harm people who come in contact with it.
If we are not meant to consume meat because other animals are more suited to consume it then we clearly should not be consuming the aforementioned, especially if we are only to consume what is "necessary".
The argument that meat eaters can find nutrients elsewhere can be applied to other foods that require the use of resources and we are talking about goods that are dependant on diesel and in some cases slave labour.
I've seen all of the documentaries you keep referring to and most don't address the recent successes of methane recovery or advancements in livestock farming that have made outside of the United States. And very few address the fact that corn and soy can be substituted to reduce greenhouse gases and food borne disease. Or the findings of the EPA in regards to the United States' greenhouse gas sources.
In regards to The China Study, this is an interpretation of data from several counties in China from the mid 70's and Mid-80's and this book's conclusions have been debunked by nutritionalists and peer reviewed studies.
Biologists believe that the have physically thrived because of our consumption of animal fats, in addition to the carbohydrates consumed by our now extinct ancestors, and although the excessive consumption of red and processed meat has been linked to disease, we have consumed meat through-out history with little ill effect.
In March 2014, The Food and Agriculture Organization had also established that the combined greenhouse gas emissions from pork, poultry, egg, dairy and buffalo production is significantly lower than that of beef (PDF) so a reduction in beef consumption is recommended by most scientists.
From the evidence i've provided it is obvious that the consumption of meat does not involve murder and that the vast majority of the points used to allege that it is are fallacious.
Vegans may have convinced themselves that this anthropomorphic false comparison is valid by simply using proof by assertion and appeals to accomplishment. But in the end this vitriolic exaggeration does not divert attention from the animal fatalities of their diet and their alleged reductions are made dubious by science.
"Speciesism" invokes prejudice by humans towards animals but is inhearently prejudicial towards humans, whose freedom of religion, freedom of concience and right to due process in law is to be revoked to make "non-human persons" of animals that would continue to consume meat, including the aforementioned wild chimps.
This omnivorous homonid takes no measures or precaution to reduce trauma and pain in the animals it hunts and consumes yet human beings are routinely accused of being inhumane with the use of generalizations about systemic failures in the meat and dairy industries and association fallacies.
Unfortunately many of the newer animal rights activists are unaware that they are using illogical arguments and do not understand the meaning of the terms used because these are not routinely discussed within their community.
For example, appeal to motive fallacy based retorts have become a rather popular with vegans and vegetarians, who routinely claim commenters are paid by the meat or dairy industry in an attempt to dispel claims online. And when a commentor states he or she does not have vested interest in their opinions, they are either told they are liars or are "brainwashed" by these industries.
It is obvious by their prevalence and routine use that these fallacies are deemed acceptable within certain groups and may be promoted within these groups. But in logic personal attacks in no way validates or invalidates any claim by default.
No logical argument has been presented to me that compelled me to believe meat consumption is or is tantamount to murder so my final conclusion is that the killing of animals for consumption does not qualify as murder.