The options are not "must walk to this place at this specific time" and "never do any exercise or take a break during your day". This type of dichotomy is drawn in so much of the back-to-office discussion. Mandating something that happens to involve, in part, something that could be beneficial, is not in itself an argument for the mandate when you can take that part by itself anyway. Like, even if it's a zoom meeting you could, at that same exact time right before the meeting, take a walk for five minutes. The mandate isn't helping you out in that respect.