A community is a group of people who have at least a set of unwritten rules. They also have something in common, may it be values, identity, or other elements helping them to establish a shared identity. These rules lead to a way of interacting with one another. They establish a common culture.
Members work hard to live up to these rules as they become a criterion to be seen as being in or out of the community. Trespassing the rules can lead to becoming an outsider.
Observing how members deal with these rules helps to see how members live the culture.
The rules which are mostly avoided, the space people talk least about, are the blind spots of that culture. They are independent of knowledge or ability individuals in that community have. They are also independent of their ability to deal with them.
Individuals will not name the blind spots assuming that they are not allowed to talk about them. Another reason may be, that they expect that no one will listen to them.
Changing the rules rarely dissolves blind spots. Highlighting does. If it can be heard.