Liberalism is an idea about how you define good and evil -- that individuals are the authority about what's good for themselves. Democracy and markets are some of the practical systems we've developed that depend on this idea.

However there are areas in which the fundamental premise that people know what's good for them breaks down, simply because of the limitations of human psychology. Addiction, bounded rationality, confirmation bias, delayed gratification, and gambler's fallacy all hinder people from acting in their own best interest, whether it's to quit smoking (addiction) or to save adequately for retirement (delayed gratification).

"Making foolish decisions against the law" is how we patch over these gaps in individuals' ability to act in their own interest.