It's definitely not just a problem at AirBnB's. It's also a problem at Korean love hotels for example https://www.youtube.com/watch?v=ggYIsnUgUdU&feature=youtu.be

AirBnB's are more affected though, as the penalty might just be a warning/fine/bad review affecting a single property. At a hotel, the entire hotel of X rooms would be affected by the bad publicity, so they have more at stake.

Because they make enough money not to care and Congress also makes enough money not to care.