Yes you are over reacting, @Ben253 but that is because you didn't expect this guest behavior and it caught you off guard. Eventually guests will find weaknesses in your rules or set-up, not because they are bad, disrespectful people but because they see the world differently than you.
I would approach the current guests via the Air BNB messaging system and in your best gracious host demeanor, apologize for not being clear about your expectations for the use of linens other than those directly supplied. Then enlist their assistance in dealing with the recycling of the linens they took so you can be prepared for the next guests. No need to make them feel bad or put them on the defensive. That is a certain way to get a bad review. You had the unlocked linen closet in their room. They rented the room and it is not beyond imagination that they thought they were to have access to the supplies in the closet. Many hosts keep additional linen and towel supplies accessable to the guest.
Obviously you are a great host and have a lovely way about you that guests appreciate and mention in their reviews.
Good luck