I am a Constitutionist or minarchist. We need a limited govt as described by the Constitution. It needs some money to get the job done.
As to sin taxes vs tariffs:
(1) you define sinful substances as alcohol, tobacco and porn. OK....problem is the defintion of sin will change. Are you a religious person? In a few years maybe churches become non gratia. Like your SUV or pickup? Lot of people don't. Can't forget firearms and ammo....can't ban them due to that pesky 2nd but they can sure tax them into oblivion.
Further, taxing only a portion of the population for govt services all will benefit from is immoral. That is cost shifting and is no different from the welfare costs the productive currently bear to support the non producers.
(2) yes tariffs are a tax. It is a cost which will be added to the price of that particular item and is therefore a user tax. That makes it fair (fair based on the assumption that some minimal level of govt is required).