Vegetarianism is similar. I know many vegetarians who only think about the poor cow who now is served as dinner instead of the thousands of animals who are killed by pesticides, fertilizers, and mechanized farming equipment needed to grow a bowl of soy beans.

If they did, would their opinion change?

I think mining is nasty, dirty, and dangerous. But I love uranium mining, even though the ore is radioactive. Why? Because each kilogram of uranium ore you pull out of the ground replaces at least ten* kilograms of coal. Uranium mining represents a net reduction to the total amount of mining that happens (with a constant energy load).

Likewise, when you go from growing plants to feed a cow to feed a human to growing plants to feed a human, you reduce the amount of plants necessary at least tenfold,* which similarly sounds like a tenfold reduction in the animals killed by farming processes.

So the thing that vegetarians aren't thinking about strengthens their argument. Are you sure you're thinking clearly about this issue, instead of trying to score points?

* I don't have the time/energy to look up the actual numbers at the moment- I'm >98% confident they're over 10 times, and strongly suspect they're less than 100.