I do think there should be some caution about staying definitively JM was doing things whilst in the employ of the NSPCC - unless the videos are date-stamped then it’s speculation as it seems the video title wasn’t chosen by him.
Regardless, it’s an appalling lack of judgement on JM’s part, putting his sex life online and linked to his employer. If it all has been uploaded/linked/posted in the 4 years since they first employed him perhaps the NSPCC is not quite as negligent as it first appeared - realistically although companies have social media clauses in their employment contracts , once initially vetted and past employment/probation no company keeps tabs on individual employees social media unless they’re alerted to an issue.
Whether they should have been alerted to an issue sooner is a question, of course. One of his colleagues should have recognised the LinkedIn kink stuff was inappropriate, at the least.