A truly interesting discussion. Perhaps kamma takes into consideration the mental formations of the individual considering an act, any act. If we are keenly aware of the precepts and instructions related to the eating of meat, and we do not participate in any proscribed act, we can be said to be acting with neutral or bright kamma. If however, we have a deep understanding of supply chain economics, and further consider the conditions under which meat is delivered to the market ( ie in the US with cruelty intense factory farming and assembly line slaughter of animals), it may be that the kamma we cultivate is brighter by having this knowledge and knowingly avoiding animal meat consumption. Having said that, this kamma is unique to that individual and not to be required of or evangelized to any other person. My sense of kamma is that it is complex, sometimes indiscernible, and is not a process that applies as a blanket rule or ordinance to all people. I suppose what I am trying to say is that kamma may be a complete process of personal ethics.
I do all I can to not violate the First Precept. I am aware that the fish that I eat on occasion for my health has been killed and brought to market for sale. I endeavor to eat less meat, and to participate as little as possible in the factory farm chain of suffering in my home country. When I was a
samanera, I can confess to eating some Thai chicken dishes that were exquisite. These were given as dana, and made for a healthy midday meal. With this in mind, what kind of kamma am I creating? I have no idea, and like most matters, I endeavor to cultivate kamma as bright as possible given my reasoning, my training, and the circumstances. I may be reborn as a bait fish.....