I confess this was a pet peeve of mine. I loathed sitting around with everyone exposing their corned and bunioned toes realeasing pungent aromas. Carpets are for walking on, not licking, and toddlers need a bit of dirt to built up immunity. And as to wearing soft shoes/slippers that other guests have worn AAGH, it's the pits. Of course I always took my shoes off if requested without a murmur.
For some reason, I haven't come across this unpleasant ritual outside the Witnesses.
In an ideal world we'd all be heeled by Manolo Blahnik, Ferragamo and Church's and shoes would be mandatory.