As an aside, it could be a small indication that this community is a.) growing a bit via reddit, and b.) reaching a critical mass where maybe StackOverflow rules should be considered.
Something like, not being able to reply to the "root" of a comment tree without some paltry number of karma, like 10.
Don't get me wrong, I don't care about karma scores, but as you point out, it isn't very hard to "farm" karma if one so chooses.
Hacker news is open to the public last time I checked.
What is pathetic is you base the community on 'First' not on how it progresses out.
They are getting down voted atm pretty fast, this style of karma harvesting by mis-representing comments not liked by the community is pretty Reddit.