In order to be socially liberal the policy maker has to extract largesse from the public coffer to promote said socially liberal programs.
How does, for example, "stop arresting people for selling, buying, or using marijuana" require extracting largesse from the public coffer?
Your example is a non-sequitur. Not enforcing laws does not extract money from the coffer, but enforcing bad law or perceived bad law does. On that front we should be repealing bad law because it runs afoul of good common sense.
Whatever side of the drug legalization fence you sit on, there are real social impacts either way. Uniform law applied in a non-uniform matter tends to de-emphasize the propriety or lack thereof WRT laws.
The surest way to get a bad law repealed is to enforce it vigorously.
“How does, for example, “stop arresting people for selling, buying, or using marijuana” require extracting largesse from the public coffer?”
Someone has to support the dopers, and that falls on those who work for a living.
Case in point...The Washington state moron who was on TV bragging how he bought the first legal sack of dope. He was promptly fired from his job.
But he said it was worth it to be the 1st legal pothead!