Well that's really just about the balance of liberal vs not. Given a certain overall tax level (which level is acceptable depends on your political worldview), one might argue that it's better to tax things that cause unwanted externalities such as environmental problems, or health issues. The latter is especially important in cases where healthcare is publicly funded. It might feel like government is micromanaging me if they tax my soda, but I really don't see how it's so much worse than taxing my paycheck. Given a certain fixed amount of taxes, I'm more than happy to see as much as possible of it be "sin" taxes to be honest.