First, none of this dissent has been suppressed in any real sense. It's still available to be read and discussed by those who desire reading and discussing such things. The current moderation policy has currently only kicked in when things have gotten largely out of hand -- which is not the case here, yet.

Second, net karma isn't a fine enough tool to express amount of detail you want it to express. The net comment on your previous comment is currently -2; congrats, you've managed to irritate less than a tenth of one percent of LW (presuming the real karma is something like -2/+0 or -3/+1)!

Third, the solution you propose hasn't been implemented anywhere that I know of. Reddit's suggested community norm (which does not apply to every subreddit) suggests considering posting constructive criticism only when one thinks it will actually help the poster improve. That's not really the case much of the time, at least on the subreddits I frequent, and it's certainly not the case often here.

Fourth, the solution you propose would, if implemented, decrease the signal-to-noise ratio of LW further.

Fifth, reddit's suggested community norm also says "[Don't c]omplain about downvotes on your posts". Therefore, I wonder how much you really think reddit is doing the community voting norm thing correctly.

I downvote any post that says "I expect I'll get downvoted for this, but..." or "the fact that I was downvoted proves I'm right!"

I don't know if there's a good solution to the problem. I would be inclined to suggest that, like with Reddit, people not downvote without leaving an explanation as to why. For instance, in addition to upvoting some of srdiamond's earlier comments, I have also downvoted some of Rain's, because a number of Rain's comments in this thread fit the pattern of 'poor arguments that support the community norms', in the same sense that srdiamond's fit the pattern of 'poor arguments that violate the community norms'; my entire point here is that, in order to cultivate more intelligent dissent, there should be more of the latter and less of the former.

Perhaps the solution is not to worry so much about my bad contrarian arguments being downvoted as to assure that bad "establishment" arguments are downvoted—as in Rain's case, they aren't. Regurgitation of arguments others have repeatedly stated should also be downvoted, no matter how good the arguments.

The reason to think an emphasis on more criticism of Rain rather than less criticism of me is that after I err, it's a difficult argument to establish that my error wasn't serious enough to avoid downvote. But when Rain negligently or intentionally misses the entire point, there's less question that he isn't benefiting the discussion. It's easier to convict of fallacy than to defend based on the fallacy being relatively trivial. There's a problem in that the two determinations are somewhat inter-related, but it doesn't eliminate the contrast.

Increasing the number of downvotes would deflate the significance of any single downvote and would probably foster more dissent. This balance may be subject to easy institutional control. Posters are allotted downvotes based on their karma, while the karma requirements for upvotes are easily satisfied, if they exist. This amounts to encouraging upvotes relative to downvotes, with the result that many bad posts are voted up and some decent posts suffer the disproportionate wrath of extreme partisans. (Note that Rain, a donor, is a partisan of SIAI.)

The editors should experiment with increasing the downvote allowance. I favor equal availability of downvotes and upvotes as optimal (but this should be thought through more carefully).