If you own a car and commute to work, then your car will contribute more to global warming than your diet will. It just happen that more people eat cows than commute to work by a car.

Comparing cars with cow is unhelpful without the correct context. At minimum we should distinguish between meat cows raised on animal feed, milk cows, and grass cows (which in places are helping the environment to reduce overgrowth). Then we need to compare those to other diets.

Regardless, cars will always be worse per person compared to eating cows. I would stick with the domestication argument.