Why can't urgent care doctors give referrals?

Long story short I fractured my finger and the ER told me I just sprained it. 2 weeks later at urgent care (went for another reason but asked for a second opinion on my finger while I was there) and another x-ray later I get confirmation it's fractured and displaced and I have to get a referral from my pcp for an orthopedic doctor.

The problem is I don't have a pcp because of insurance issues (thus the reason for ER and urgent care) currently and I'm told my insurance won't start until October 1st. Won't my finger be healed by then? Why can't the Urgent Care doctor give me a referral if they're doctors who saw/confirmed my injury? Like clearly I have a fracture that is healing wrong, you just told me. Why do I have to go through a PCP who might just make me redo everything AGAIN when I already know what's going on and have a medical professional who agrees with me?