No 'slippery slope' about it. It's spelled out in black & white with no exceptions nor exemptions. JustOSBI is between a rock and a hard place.
Oklahoma law says that anyone who is “ineligible to possess a pistol due to any provision of law of this state or the United States Code” is ineligible for an SDA permit based on the mandatory preclusions.
Under United States Code, anyone who uses marijuana is a prohibited person (18-922 (g) 3).
Issuing a permit to someone who admits to using marijuana would require OSBI to ignore both state and federal law. That’s a slippery slope I suppose.