I could never eat horse meat. Horses are fully capable of thougts, sentience, and emotions. Any animal that is capable of love is off the menu for me. Not only that humans have used horses for millenia for work and battle and transportation. I find it apprehensible that one could justify eating what should be considered a companion animal. Where would we be as a species today without the aide of horses for trade tranport among other things. It definitely would have slowed us down as a developing civilization. Same with cows I don't eat them either all they do is eat grass all day they hurt no one and nothing and don't deserve to die. I can't eat pig either or basically most any animal for moral reasons. Humans don't need meat to survive. The only thing meat has that plants don't is vitamin B12 and there is a perfectly fine synthetic B12 called cyanocobalamin. If not that then one can get B12 from milk. So long as the milk comes from a humane no kill farm with well treated cows then there is no moral issue in that regard. Besides cows are known to produce too much milk; more than it's offspring is able to consume, so it's not really stealing from it's young either. In the amino acid department brown rice, whole grains, beans, nuts, soy, veggies, fruits, all those combined posses a perfect amino acid completeness score all one would need is a cyanocobalamin.
Enjoying meat when you biologically don't need it is basically like enjoying the pain and suffering of an innocent lifeform.. unacceptable.