Use of Airbnb now requires users to pledge to treat everyone with respect

What is the Community Commitment? You commit to treat everyone—regardless of race, religion, national origin, ethnicity, disability, sex, gender identity, sexual orientation or age—with respect, and without judgement or bias.

Also, they're serious about it:

If you decline the commitment, you won’t be able to host or book using Airbnb, and you have the option to cancel your account. Once your account is cancelled, future booked trips will be cancelled. You will still be able to browse Airbnb but you won’t be able to book any reservations or host any guests.