The RF have teams that scour the press before it is even printed for harmful comments, and fire off lawyer's letters threatening legal action before its done.
(We know this because of Prince Harry's Statement to the Press, where he helpfully if somewhat unwisely put it in writing for us - "the nightly legal battles to keep defamatory stories out of papers").
If they thought it was untrue, anyone reporting this story would have been subject to legal threats of injunction and defamation action, with massive damages. They wouldn't just ignore it.
Instead, the RF have resorted to their other technique, of ignoring people who challenge them. As with Meghan Markle's immediate family. Its fairly successful - a lot of people will assume the RF is all good and any accuser is all bad/mad/must be lying.
You will note that the Palace makes no comment about how important it is to protect young girls from predatory men. Nothing at all. But plenty to say on press intusion into their lives.
The RF are ruthless. That's their practised mode of survival as a firm.