A very misunderstood passage indeed.
An interesting exercise is to insert your favorite tyrant in place of "rulers" in this passage.

Let every soul be subject to Pol Pot. For there is no authority except from God, and Pol Pot is appointed by God. Therefore whoever resists Pol Pot resists the ordinance of God, and those who resist will bring judgment on themselves. For Pol Pot is not a terror to good works, but to evil. Do you want to be unafraid of Pol Pot? Do what is good, and you will have praise from the same. For Pol Pot is God’s minister to you for good. But if you do evil, be afraid; for Pol Pot does not bear the sword in vain; for Pol Pot is God’s minister, an avenger to execute wrath on him who practices evil. Therefore you must be subject, not only because of wrath but also for conscience’ sake. For because of this you also pay taxes, for Pol Pot is God’s ministers attending continually to this very thing.