Guest lies in review, booking.com does nothing

So a review is left on my partner page by a woman who says a staff member at the front desk made a rude comment to her. I reviewed the audio/video file from cctv and find out it was the male guest ahead of her that made the comment. I contacted the male guest who acknowledged that he indeed made the comment (which was a joke that everyone else in the lobby thinks is funny) and he even emails booking.com and tells them it was him, not the front desk person.

Of course booking.com leaves the review up even though it is an outright lie. I have read of this happening to other hotel owners and they have no recourse either. It is very apparent that booking.com doesn't listen to their partners. Why are we still using them ?