"But temperance also can be created by coercion. Taxing is a good coercive device. To keep downtown shoppers temperate in their use of parking space we introduce parking meters for short periods, and traffic fines for longer ones. We need not actually forbid a citizen to park as long as he wants to; we need merely make it increasingly expensive for him to do so. Not prohibition, but carefully biased options are what we offer him. A Madison Avenue man might call this persuasion; I prefer the greater candor of the word coercion."

-- The Tragedy of the Commons

I recommend the whole paper as a good think on the unintended consequences of not biasing the options of people away from collective irresponsibility.

Because their choices have consequences for others.

You might not care about some health risk, but when you get sick, your family is going to be affected, your coworkers are going to be affected, and society has to pay for you to get well (by paying more for health insurance).

And we're social animals. We care about one another. And caring sometimes means that we nudge people into a direction that makes them healthier.

(I don't actually know if red meat is dangerous enough to justify a tax, but for the sake of argument, let's assume it is)