A dog (and other carnivores) has 2 times the stomach acid (to break down the meat) and 1/3 the intestines (to expel the meat before it has a chance to putrefy).
Yes, meat rots inside you. It stay too long and so starts to becomes a burden on your liver.
We aren't 100 percent herbivores, though. Meat has been such a part of our history that our appendix has atrophied. It was once an organ to ferment grass (like a bunny rabbit has). So we can't live on the lawn - alas.
HAPPY VEGETARIAN DAY !!!