It doesn't matter to non-believers does it? It does to believers. King Charles is a believer and the whole ceremony has a deep religious significance. So deep that it held her late Maj. to her duty for the whole of her long life.
The 'men in posh frocks' are enacting a time-honoured religious ritual. If you don't believe - it's easy, don't believe and laugh. It's still a special oil, coming from the Mount of Olives etc..
But have a little grace to allow others their beliefs without mocking, please.