I don't want to get too sidetracked by the issue of morality and meat because I don't consider it to be a fundamentally moral issue (and I could be wrong about that). I am a big fan of selfishness, but it's a tricky topic. I have discovered, slowly and reluctantly at times, that there is nothing more pleasurable than to live a virtuous life, and to do that we need to apply great discrimination in choosing how to spend our short time in the world. If a man is surrounded by food and wine, and can beckon servants at the snap of his fingers, it might appear that his happiness is guaranteed, but if he simply reclines and enjoys carnal pleasures all day, he will soon become restless and dissatisfied. We cannot enjoy rest without work, food without hunger, or companionship without loneliness.
Diet is subject to the same constraints. Meat is all well and good, but plants are absolutely delicous and extremely nutritous. I think their delicate flavour can only be appreciated to the full by relinquishing or limiting rich foods, acohol, coffee and animal proteins. To give an example, someone who is used to a diet of processed foods will recoil from a simple dish of lightly cooked grains and plants or even simply prepared meat, if that is one's preference, washed down with a wholesome glass of fresh water rather than soda or beer, because it will taste alien and insipid to them. They are accustomed to the harmful additives and flavour enhancers that the food industry loves to use. So "selfish motives" are always the driving force, but we need to arrive at a deep understanding of self and the options available in the world to explore them fully.
To focus more on the subject of meat, I have killed animals in my life and the memory of each such event remains with me to this day. If I could live my life over I would not repeat those acts, so, out of a selfish regard for my emotional tranquillity and my anguish in response to the suffering of animals, I have learned that I prefer not to kill them, even by proxy, if that is avoidable. I think everyone must follow their own path and their own heart in this regard.