I'm assuming 'flagkilled' means enough users flagged these articles. If the moderators actively killed all these articles (some are to newspapers with millions of readers, and not link farms or whatever) that would be .. interesting, but ok.

I think HN mods are nice people and are probably unaware. I did send them emails, but I didn't get a reply (which is understandable given this is Saturday night in the USA). I suspect either a pro uber voting ring or a software bug.