Did you just not read two paragraphs below that where it says "What if I decline the commitment?", or do you just think it's pertinent for some reason?

Seems pretty clear: You can't discriminate, if you do we terminate your account at our discretion.

Edit: I read the question only in the narrow sense of "what if you refuse to accept the new policy" v.s. "what if you break the policy once you accept it?".

The answer to the latter seems to be:

1. You have to agree to Airbnb's TOS to use their site: https://www.airbnb.com/terms

2. Section 24.C ("Termination for breach, suspension and other measures") refers to section 14 ("User Conduct") which says you can't violate the "Policies and Community Guidelines" which links to https://www.airbnb.com/help/topic/250/terms---policies

3. That links to their nondiscrimination policy (https://www.airbnb.com/help/topic/533/nondiscrimination), which seems to be the longer legalese version of what the linked blogpost is a tl;dr of.