I took a long break from MN and now only visit royal threads once in a blue moon, so I don't know about recently.
But when the Virginia Giuffre scandal first broke there were definitely tons and tons of threads and comments here defending him. Absolutely tons of comments calling Virginia a liar, a slut, a gold-digger, stating that she was lying for attention, that she was targeting PA for a payout, that she chose to become a prostitute (along with several "why didn't she just leave" type comments) and was "now playing the victim card". I remember one particularly awful comment saying "girls of that age know exactly what they're doing when they sleep with older rich men."
Lots of comments playing devil's advocate, saying that VG appeared to consent so how could PA possibly be expected to know that she'd been trafficked. Lots of "well technically she was above the age of consent so no crime has been committed." And of course lots and lots of the usual "innocent until proven guilty!!" and "what a disgraceful thread, this is just a witchhunt" (see the current Phillip Schofield threads, which are also full of "witchhunt" and "no proof of grooming" and "well the boy was above the age of consent when the relationship became sexual so PS hasn't done anything illegal, you're just enjoying a witchhunt against an openly gay man!"comments. Hell, if you google "Jimmy Savile Mumsnet", a thread comes up with the title "AIBU to think that describing Jimmy Saville as a pervert is wrong" with a long OP about how there's no evidence that JS did anything wrong, complete with "I'm not calling his accusers liars but....")
I remember one thread that got derailed into very weird discussions about the photo of PA with his arm around her waist, with posters getting deep into forensic analysis of the photo, comparing the exact hexadecimal colour code tone of the pixels on his hand with that of his face, to show that his hand was a different colour from his face and that proved that the photo had been photoshopped. When not even PA denied that the photo was real. That's quite an extreme level of investment into proving PA's innocence.
Even after the TV interview there were threads taking the piss out of him and saying he came across very badly, there were still comments saying "well technically he didn't do anything wrong" and comments calling VG a liar and a gold digger who'd schemed to target PA to get a big payout.
Anyone claiming that no one on Mumsnet defended Prince Andrew either hasn't been on Mumsnet very long, doesn't read many royal threads, or is simply lying for their own agenda.