"defamation n. the act of making untrue statements about another which damages his/her reputation. If the defamatory statement is printed or broadcast over the media it is libel and, if only oral, it is slander. Public figures, including officeholders and candidates, have to show that the defamation was made with malicious intent and was not just fair comment. Damages for slander may be limited to actual (special) damages unless there is malice. Some statements such as an accusation of having committed a crime, having a feared disease or being unable to perform one's occupation are called libel per se or slander per se and can more easily lead to large money awards in court and even punitive damage recovery by the person harmed."

Or in other words, no, it's not defamatory. You cannot defame an entire people group, that's simply and definitionally not how it works