To get what you want, you must first understand the perspective of others. Understand their motivations and incentives and then take the path of least resistance. Apparently pharmacists can be held personally liable for narcotic law violations. When you pay in cash instead of with an insurance claim you are not in the system. Not all cash payers are trouble, but a noticeably higher proportion of cash payers are trouble. The same goes for being a new patient/customer, saying you lost your bottle, or needing an early refill. Assholes who re-sell their methylphenidate are why DEA, docs, pharmacies, etc. are putting up barriers.
As you noted this can be hostile to the people who need to take their meds. You can get stuck in a vicious cycle where being in urgent need is interpreted as suspicious which leads to denials and lack of meds makes you more harried. It's worst for people who are physically dependent on their meds and will who go into withdrawl, pain, or become very unproductive.
I've had similar experiences to OP, and I can also attest to the fact that it is absolutely obnoxious to be treated like a criminal in the normal course of filling your daily prescription.
Sometimes you have to travel for work, and because methylphenidate is such a threat to society (it isn't) you can't fill prescriptions out of state. So you talk to your doctor to get a special prescription with written instructions to allow it to be filled 4 days early (gasp!) so you can fill it before your trip. The pharmacist then rejects filling it for you, for reasons they refuse to explain.
I see a doctor in my home state, about an hour's drive from where I currently live. I see this doctor once every three months. I've seen him for 10 years. I would like to continue to see him. Recently I was put on a light sleep aid for anxiety reasons, I went to fill this prescription (which I have to do in the state that I see the doctor in). I was told my insurance only allows me to get a 2 week supply, and I'll have to come back in 2 weeks later to fill the rest of the 30 day prescription the doctor wrote. When I asked how much it would cost to just pay out of pocket, it was negligable, 20 dollars or so. When I asked to just pay for it myself to avoid making a long trip again 2 weeks later, the pharmacist decided to deny giving me anything.
As you noted this can be hostile to the people who need to take their meds. You can get stuck in a vicious cycle where being in urgent need is interpreted as suspicious which leads to denials and lack of meds makes you more harried. It's worst for people who are physically dependent on their meds and will who go into withdrawl, pain, or become very unproductive.