I can't see any fault with the court's reasoning. But there was an interesting finding:

"[Justice] Perell did recognize that DD’s lies about taking the pill undermined PP’s consent to their sexual activity – potentially making him the victim of a civil sexual assault."

The legality of sexual activity between two adults hinges on the consent of both parties. In this case, PP was deceived into giving consent, rendering that consent invalid. It's the equivalent of a woman saying to a man, "I'll have sex with you but only if you've had a vasectomy." If the man lies about it to have sex, the woman has been deceived into giving consent.

However I question the use of the term "civil sexual assault." As far as I know, sexual assault is a criminal offence only, although a victim may sue for damages in a civil trial.