I don't think there was any implication made that the tenants could not go pick up their mail from the post office. Or did I miss something obvious?!
I didn't see where it was mentioned one way or the other.
If the tenants must go to the post office to pick up their mail, however, that can be a problem. Some tenants may be restricted in their mobility. Some tenants may have time constraints that restrict their ability to get to the post office. Some tenants may be restricted by the cost of travel on a daily basis to the post office ...
The refusal of the mail carrier to deliver, backed apparently by the post office's determination that the mail room is unsafe as is, means that someone needs to do something. If the mail room is really hazardous (and I think there needs to be a clear determination that this is the case), then the property owner needs to take action to make it safe for the mail carrier, so his tenants are serviced - perhaps by converting the better-ventilated and empty day care into a mail room or, perhaps, by wiring the mail room to allow for the installation of an air conditioner in the room, or whatever.
I am still interested in who pinesofwestbury is in all of this.