It isn't really clever, but I think biasing the pubic perception of LessWrong discourse is the point of doing so. I don't know how much good it will do to try and alleviate this by appealing to their sense of honour.
I used to think this kind of thing isn't much of a problem, since karma is eventually restored, but then looking at my own and some other posters history I've noticed that the older comments don't seem to recover karma, or recover it so slowly that they haven't done so in 8+ months. In effect this reduces the amount of information one can glean about shifting positions on LW over the long term, or rather might create false impressions on current distribution of opinions regarding old arguments. Especially newcomers may be pretty affected in their assessment of issues by this.
Now let me emphasise that there is a difference between blindly down voting and reading through someone's commenting history, upvoting and down voting comments as you go along. The end result may well be a 40 point karma boost or hit for the handle. But the problem however might be in who one ends up picking for such review. Either someone you like a lot or someone you dislike a lot. Keep that in mind when reading through someone's history. Don't conjure up false rationalizations of the motives for what you are doing.
Being a binge reader, I solve this by precommiting to only voting on one comment per page if I simply feel compelled to read up on all of someone's stuff.
It isn't really clever, but I think biasing the pubic perception of LessWrong discourse is the point of doing so. I don't know how much good it will do to try and alleviate this by appealing to their sense of honour.
From what I can tell the point is sometimes to discredit and warn people who someone thinks are straying close to topics that the someone doesn't like. Bleh, too tired for clear grammar. Anyway. If so, this is incredibly dangerous; it can easily provoke escalation. Don't be stupid. (Edit: I mean, "You who are considering engaging in the above-mentioned retaliation, don't be stupid." Sorry that wasn't clear.)
People who go back and downvote every post or comment a Less Wrong user has ever made, please, stop doing that. It's a clever way to pull information cascades in your direction but it is clearly an abuse of the content filtering system. It's also highly dishonorable. If you truly must use such tactics then downvoting a few of your enemy's top level posts is much less evil; your enemy loses the karma and takes the hint without your severely biasing the public perception of Less Wrong's discourse.
(I just lost over 200 karma in a few minutes and that'll probably continue for awhile. This happens to me every few weeks. Edit: I mean it's been happening every few weeks for a few months for a total of only three or four. Between 400 and 700 karma lost total I think? I don't mean to overstate the problem.)