I'm going to summarise my comments into an answer.
30k is not going to do any good for braking. To brake the motor, you would have to be able to absorb about as much power as you put into the motor. 30k as a load is a teensy tinesy fraction of the driving current. Besides which, you would want to switch a braking load into the circuit to stop, and out to run. There are no switches or relays in your circuit for braking. Also consider: The motor takes in over 1500 watts when running. How much of that could 2 one watt parts absorb?
Since the resistors are always in the circuit, they are continuously dissipating power. 30k at 120VAC is about 0.5 watts. They probably split it into a couple of 15k, 1 watt resistors so as to keep them from running too hot.
The only thing that makes sense is for those resistors to be used as a discharge path for capacitors in the motor. Without the resistors, any capacitors in the motor that are across the 120VAC input can stay charged after you shut off the motor. That can give you a nasty shock if you touch the motor connections - even though the power is off. Universal motors like the ones in kitchen mixers have capacitors across the AC supply to reduce intereference - and they are required to have a resistor in parallel to bleed off the charge. Larger motors like yours may have a start and a run capacitor. These can also remain charged when you shut off the power, making a bleeder resistor also be a good idea for these motors.
Bleeder resistors are usually in parallel to the capacitors rather than being external in a controller board. So, yours aren't really in the place you'd expect them to be.
But, its the only usage that makes sense.
Maybe the motor itself doesn't have bleeders, and the folks designing the controller decided they'd rather have a bleeder after all.