Restroom doors swing in because?????
Couple of reasons... ADA has 18" on the pull side of a door and most are in apposing alcoves for women/mens rooms.
Bigger reason is the Mechanical Code... it requires bathrooms be kept at a ventilation rate and allows "make-up" air for the space to be taken from hallways etc. Although typically these days hvac contractors will put a supply duct in the room instead.... used to be under older codes when using make up air from the hallway you had to put in those old grills at the bottom of the door for air flow otherwise if you pushed the door in too quickly you could hear the ceiling tiles rattle from the change of air pressure of you opening the door.
Now ends the random ramblings of a construction code geek.... feel free to return to previous programming