I have no problem with feet in shoes on chairs that are not being used. Bare feet, or feet in hose, I have a problem with, only because I can really smell foot stink easily.
Years ago, I worked at a company that had a little reading nook set aside for people on their breaks. There were two cushioned chairs up against a windowsill, and it was nice and quiet and I loved reading there on my lunch break. An older lady used to come by sometimes, kick off her shoes, and prop her feet up on the windowsill while she laid back in the chair and closed her eyes. Unfortunately, her feet stunk badly and I always had to leave once she did that. If she'd kept her shoes on, I wouldn't have cared.