@Sarah5258
Thanks for letting us know....I wasn't sure myself. However, I do remember quite a few conversations on the CC about this. The only way to truly block a guest from seeing/booking your listing (as I recall) is to block them in the actual message thread:
Block a Guest
https://www.airbnb.com/help/article/2020

The choices for why you are blocking may not actually fit the scenario of "annoying", but I guess you can choose they are being rude as that kinda fits "annoying".