I have no problem with boutique and unique hotels posting listings on AirBnb. I think most people would agree that AirBnb is not appropriate for big hotel chains. I see Crowne Plaza and La Quinta listings.
The suspect thing is that the AirBnb price is often higher than the price I would get if I booked directly from the hotel's website, especially when you include cleaning fee. Sometimes they are super below the regular price which screams scam listing to me. If enough AirBnb users get burned by scam listings, it hurts AirBnb's overall reputation and so hurts legitimate hosts.
Per the link I keep seeing on this thread, chains violate the listing requirement:
"Properties should have a unique, independent environment and style (for example, boutique or lifestyle hotels, not mass-market chains)."
To report a Profile, go to the host's profile page. This one is literally titled CrownePlaza, hopefully it no longer works if you click it:
https://www.airbnb.com/users/show/329422732
Scroll to the bottom and you will see 'Report this profile'
I report the profile and include that same quote saying the profile is in violation of AirBnb's policy.