Apparently, the British royal family came to the realization a couple of decades ago that it was not an adequate way of avoiding drama anymore.

> With a less deferential and increasingly aggressive media landscape, the strategy of "Never complain, never explain" was abandoned by Prince Charles (the future King Charles III) and his wife Diana, Princess of Wales, in the 1990s.

I am not sure whether the motto is the cause there or the fact that Charles had a lot of drama going on...

Most people or organisations can just wait until the public get bored of that issue and forget about them, but for the Royals that doesn't work because they are _always_ in the public eye. There's enough demand for Royal news that if nothing else is happening, the press will quite happily rake over old sores. The only way out is to feed the press with constant new material.

It later says that Prince Harry and others were taught that motto in childhood - so that was a temporary slip.