Tell ya what, I will put a bowl of carefully selected dog food or meat out and a bowl of fruits and vegetables out and let Pepper the Found Dog make his own choice.
You're gonna feed me WHAT??
I agree that the practices you listed are horrible and we should take every measure to eliminate and/or avoid them.
HOWEVER, unless I missed something, I do believe that dogs and cats are primarily carnivores who eats grasses and plants mainly to supplement their vitamins and minerals. Put it this way, Pepper has never drug a turnip or ear of corn back to the campsite.
For that matter, the doggone sneak has never stolen the buns, lettuce or tomatoes when we are grilling burgers either! And we aren't even gonna talk about what happened to the chicken breasts that were grilling under a COVERED grill when we went to town and left Pepper in charge of camp. Grrrrrr!
If eating meat is unhealthy for them, you can bet it is for the same reasons that so much of our food is unhealthy - what man has added to it and taken out of it during processing. DQ