This is false, and I'll go one better.
Despite AirBnb's policy for guests to "not write biased or inauthentic reviews as a form of retaliation against a Host who enforces a policy or rule" this is obviously contradicted in the following response from your support team. (This is what I tried to argue when a recent guest left a retaliatory 1-star review (my only one after 4 years). Here's AirBnb's response...
"In order for a review to be removed, the contents of the review has to be in violation of our policies, after checking several times through the review which was left for you, the review did not violate our polices. We also do not remove review based off truth or fairness."
"Based on the content in the review, we could not find any content or language that goes against our policies, we understand that this may seem unfair to you and wish that there was something else that could be done however, we are not able to make exceptions or override the policies."
So, it really doesn't appear to matter that a guest can violate house rules, or that his review was untruthful, or that he admitted in his review that he violated house rules, only that his review didn't violate AirBnb policy....which is for guests to respect and follow house rules and not retaliate when a host tries to enforce them.