The basic thing about eating dog is that it is a scavenger and a meat eater itself. It is not good to eat animals that consume other mammals, they carry a lot of bacteria and parasites in their own meat. The scavenging aspect is fairly obvious. Food from bins, their own and other animals faeces...
Ever seen a dog "farm"? I have. If you have even a whisper of a soul you'd change your opinion after that. No living thing should have to suffer the way those dogs do. In their thousands. It really is horrendous.
Caged up with 20-30 other dogs.
Living in their own excrement.
Beaten...
I suppose if one is fundamentally opposed to the use of animals in sport, a case can be made. Don't see them up at the track protesting any other day of the week though. Too busy shagging undercover coppers?