I need a way to turn off the hijab

I think you can disable any Maxis clothing you want for random by creating a CAS override in the sims4 studio and then edit the package so that allow for random is disabled. I made one for the eyeball ring.

You can even deselect all ages for it, then it won't even show up in CAS.

I got nothing against the hijab in the game but I can understand why people might not want it to show up on festivals and other situational outfits.