@Lance141 When a guest sends a request, they can request anything they want, from asking that you waive your house rules or length of stay minimum to asking if they can bring their pet iguana.
It's quite annoying that your calendar gets blocked, but abut all you can do is message back, telling them that as stated on your listing, you have a 3 night minimum, and to please withdraw the request, at which point, your calendar would unblock. And you can always decline the request, which will also free up the dates, but affect your Acceptance rating.
I would suggest that you ask Airbnb to unblock the dates when you get a request outside your stated parameters, but it is quite frustrating to try to reach Airbnb right now.
In your last line, you referred to Inquiries- you do know the difference between an Inquiry and a Request, right?