Earlier quoted context omitted.
The point of that isn't "what is said under oath is guaranteed true" rather "one side isn't worried about perjury for their claims if they are indeed lying while the other avoids making their claims under oath". Also, it doesn't make sense to address this arbiter as "Mr." - You can read a bit about her here https://www.courts.wa.gov/appellate_trial_courts/bios/?fa=at...
I find it hard to believe that someone who was willing to bring false rape allegations would be unwilling to perjure themselves under oath. I also don't really care what the gender of the arbiter is.
It's not okay to misgender a person because you personally don't care. And if you truly don't care, why take the extra effort to use gendered phrasing in the first place?