@Diana1027 As another poster suggested, turn off Instant Book until you get more experienced with vetting guests and hosting.
These guests are rude, disrespectful and self-absorbed.
Using your shelf as a cutting board, while clueless, is minor compared to some of the things hosts have to deal with. If that's going to put you over the edge, you may want to reconsider hosting. Not all guests are going to respect your beautiful home the way you would like them to- some will leave it spotless, some will leave it a pigsty. An Airbnb should be fairly bulletproof, not filled with expensive things ( not that a kitchen shelf is a luxury item).
The inital message you received from this guest was a red flag. Bad guests send messages which only center on their own needs and expectations. Good guests send messages like "Hi XX, just found your listing and it looks perfect for us. My husband and I would be coming to attend our nephew's graduation and our grown son may come as well-if he decides to, I will add him to the reservation. Looking forward to meeting you and staying at your lovely place."
So when you get an initial message that's a red flag, respond by asking them for further info on themselves and the purpose of their trip and ask questions to ensure that they have thoroughly read the listing description. If they don't answer your messages, contact Airbnb to tell them this and that you need them to contact the guest and tell them to communicate.
Use the Airbnb messaging function to communicate with guests, not texting or phone calls, if possible. That way there is a record of what transpired for Airbnb to look at should there be any disputes.
All of my guests have been lovely, but I host a private room in my home- they can't get away with much and I've gotten pretty adept at vetting them through messaging and looking at their past reviews.