I think it is funny to make this an ethics discussion when there is plenty of evidence that bacon and sausage cause digestive tract cancers. Meat is also pretty expensive unless heavily subsidized.
I think the main focus should be on educating people that a healthy diet contains a very small amount of meat even though the meat industry has managed to make people think it should be in every meal.
The car/bus comparison is useful, the others aren't because they travel at different speeds.
Probably walking can still move more people than cars. If walking is 5 kph and driving is 50, people need to take 10x less space to break even. They probably do, as cars need to keep distance.