It is not clear what is meant by "do civil rights attach to defamation by a government entity"--civil rights have nothing to do with defamation, and vice versa. Defamation is a common law tort; it occurs when a person or entity knowingly or with disregard for the truth makes a negative factual statement (not an opinion--it must be a factual statement) about someone, which statement damages that person's reputation. If defamation is committed, a person's race, religion, sex, etc. are irrelevant; there is liability due to defamation. And conversely, if the statement is not defamatory, it is not made defamatory because someone is in a protected category. A given governmental action could possibly give rise to civil rights and defamation claims, but they would be independent of each other.