A first fact about nutrition is how the human organism could maintain its functions without requiring meat from other species. What happens in this time, where people in general should know that, it must lead to thinking before proceeding with the same behavior. Taking into account the actual numbers for the human species any massive behavior interacts transcendentally with the stability of the ecosystem and its statistics, producing extinctions and harmful interactions with the natural cycles of regeneration. This is what happens today, and the responsibility comes principally at the individual level as anyone is sufficiently rational to understand basic realities like this and act accordingly. These are extremely serious circumstances that harm the present and especially the future.
If you think on it, the act of eating some life form, one that has independent life and autonomy, has multiple connotations for a rational being. Living in the wild, there aren't options most of the time, but focusing the context of an evolved location with enough logistics to provide the necessary nutrients for the human organism, it starts another important set of consequences for who choose to forget that in front of this solid truth. Not only about nutrition, also for experimentation or using other species like a production source, or with other words, a business with lucrative purposes.
The fictional character James Bond had a license to kill, thus this man would judge about the life of others and then decide about their future. Lamentably, this kind of decisions are normally in the realm of the engineer that developed life, because assume it or not, there's evidence of a superior intelligence behind evolution and science. Anyone should take care of what licenses take for granted, and at what level, because in the eventuality of not having a particular one, perhaps it's more problematic than convenient, in an overall view. To be rational sometimes is a burden as you cannot answer with a roar.