Missouri Executive Order 44 (eat your heart out, George) was signed by Lilburn Boggs on October 23, 1838, and ordered that Mormons in the state be “exterminated” or exiled. This destroyed Boggs’ political career, but the order wasn’t formally rescinded until 1976 as a goodwill gesture by Governor Kit Bond. Zombie laws and orders are a hell of a drug that I imagine keep lawyers up at night.
Well no, not at all. Please read the order itself (bottom of the linked Wikipedia article). It’s specifically ordering the state’s militia to do this. And it’s not even a generic order to the militia; it directs specific, named officers to raise X number of troops under their command for the extermination. The governor is vesting this authority in specific people who died long, long ago. By 1976, the order wouldn’t have been actionable by anybody even as written (let alone by actual legal standards under which anyone would definitely be convicted); rescinding it was purely a ceremonial act of goodwill.
It definitely still would not hold water if it were telling citizens (or even generic militia members) they could freely kill Mormons, but it’s not even that murky. The loophole not only doesn’t exist in practice, but it doesn’t exist even in writing.