HPD includes (used to include?) a form to sign when applying for a permit saying you understand Medical Marijuana, while legal, makes you prohibited from possessing firearms.
On June 14, 2000, Governor Ben Cayetano signed Senate Bill 862, which established the Hawaii Medical Marijuana Act to remove state-level criminal penalties on the use, possession and cultivation of medical marijuana (also referred to as medical weed, medical pot or medical cannabis) by patients who possess a written certification/medical marijuana recommendation from their physician. Qualifying patients must register with the Narcotics Enforcement Division (NED). Patients or their caregivers may possess up to 3 ounces of usable marijuana, and may cultivate up to seven marijuana plants, three of which may be mature. What the law didn't do was decriminalize growing pot for sale.
In 2015, the legislature began efforts to allow for MM dispensaries. In January 2015, passage of SB 321 allowed for a licensing system for marijuana growers and dispensaries. It's taken over 2 years for that bill to see the first dispensaries open.
2013 is about the timeframe I remember the form from HPD being included. It's been over 2 years since I applied for a permit, so I don't know it that form's still required, but the HPD application has a disqualifying question:
Are you authorized to utilize marijuana for medical purposes?
Answer "Yes", and the permit will be denied.
http://honolulupd.org/downloads/SOHFirearmsApplicationQues10_2017.pdfRegardless of the Hawaii law, there is a question on the ATF 4473 that asks the same thing:
Are you an unlawful user of, or addicted to, marijuana or any depressant, stimulant, narcotic drug, or any other controlled substance?
Warning: The use or possession of marijuana remains unlawful under Federal law regardless of whether it has been legalized or
decriminalized for medicinal or recreational purposes in the state where you reside.
https://www.atf.gov/file/61446/downloadSo, HPD is only complying with Federal Firearms laws.