I don't think she's being disingenuous
loved it when she said to Stephanie "let the big bad wolf handle it"
she was wrong about who put the underwear on the table, there were all 3 there
but John just got silly & dramatic by saying that the owner of knickers should be named and shamed, that was where he let himself down.
John showed Stephanie up , for a laugh, yet he'd already said he was worried about her when she gets out the house and is quick to give her advice - You wouldn't want an enemy in John !