It is really not semantics, because of the amount of control that academies have over the work the teachers do, and because of their freedom to hire and fire teachers.
By making it harder for people to use the site casually, you tip the balance in favor of spammers and away from people who actually have an interest, and therefore usually some knowledge, on a given subject.
You must agree that for almost every web-based product, designers and product managers can safely decide to completely ignore all people who have requirements like yours without it ever affecting their success.