In general, so-called "etiquette experts" look unfavourably on shoes-off policies.
They sometimes grudgingly allow that one can ask guests to remove their shoes, but with the qualification that one should provide guests with slippers.
I think this shows they are on another planet. I know there are many countries like Russia and Japan, where guests will be given slippers by the host, but whenever I have sought peoples' opinion on borrowed slippers, whether online or in person they tell me they really don't like the idea of borrowing slippers.
It seems clear to me that while people in Japan and Russia may not mind wearing somebody else's slippers, people in the UK, and probably the USA too, would prefer socks or bare feet to borrowed slippers. The fact that so-called "etiquette experts" are oblivious to this shows that they are out of touch with the modern world.