Shoes are designed for various occasions and activities of daily living. I heard of an interesting case where guests were asked to remove their shoes before entering a black-tie event at a residence in the US. Many turned back because they were not forewarned.
I however think the real reason could be different, ranging from unsightly pedicure and odour issues, or simply wearing the wrong socks. Perhaps the real reason was they wore special shoe that were an extension of their personal brand and that is currency in social settings.
