But if so, why not try to camouflage it as something more generic, to try to avoid notifying Airbnb? I am tech savvy enough and have marketing notifications turned off, but I would assume that they are simply not honouring the setting somehow if I received an ad for Airbnb.

Now Airbnb knows to change their key or something if possible, and I'll be very suspicious of any notifications from any app in the future, especially Airbnb.