What's the purpose of this circuit section?
Yes, that's exactly what it is. The current through R2 is CV1/3.3K and that current (minus a small amount of base current) flows from the collector of Q1 into the bias pin.

The bias pin is a couple diode drops above the negative rail so the maximum current is about (1.5V - V-)/8.2K before Q1 saturates. 

The diode D1 protects Q1's base-emitter junction against reverse breakdown.