My memory is very vague about this, especially since it was a one-line mention in one of the books, but as I recall, the Kilrathi did NOT exterminate the Hari. Instead, the Hari committed mass suicide rather than surrender. (IIRC, the Kilrathi may have exterminated the Shata/Utara, but even that I'm not sure of) In general, the discussion about whether the Kilrathi were out to exterminate us or not didn't really get concluded properly. A lot of stuff was ignored, the most obvious being the fact that Confed was able to capture a planet with human slaves in the last year of the war - AFTER the imperial decree that supposedly meant the extermination of humanity. In other words, the imperial decree was either widely ignored, or repealed.