In that example the circumstantial evidence would have to be very compelling to convict for robbery. After all, the person found with the purse could have just picked it up after the thief discarded it. On the other hand, a charge of possession of stolen property could be an option leading to conviction.

The judge in this case did not, repeat did not, ignore the evidence. He accounted for all of it, and explained why the incriminating evidence was insufficient to determine that a sexual assault took place. He also noted that there was evidence that the woman entered the cab in an intoxicated but apparently competent state, for the purpose of consent. The mystery is why she passed out and soiled herself within ten minutes of entering the cab. That and the mystery of why police pursued charges on such weak evidence.