I know it feels like discrimination.

But the general public does not realize that everything a pharmacist does on that shift comes back on THEM legally. (on their private license which may be suspended, or fined, often starting at $1000per)

I worked contingent for many years, going to a new different pharmacy often, sometimes every day, sometimes every week.

When working that way, one does not have the history of the patients to the extent and understanding that the regular staff has. C-II substances can be problematic. I used to go into the computer history, and do a little detective work. But I can tell you I saw some horrific abuses with C-IIs and C-IIIs in some places I worked.
I did not return to those places. If a pharmacist has been sanctioned for an error or involved in a legal problem with anything including pain meds, they will tend to be guarded with everyone after that.

I certainly don't consider myself biased, but I have refused a few on occasions. And I have found many FORGED situations with actual illegal activities where I have called police and/or confiscated the written order. So it is very hard to generalize and say BIAS when there may be another reason(s) for what you encountered. This is my 40+yrs experience talking.

If I had my say....I'd say DOCTORS are far more problematic that Pharmacists. The younger ones today, are a bit more afraid of C-II abuse than the more experienced ones.