that is any member of the community's right, right?
If "right" means "thing it is technically possible for them to do" then it certainly is. If it means something more like "thing LWers are generally happy to see done", I think it probably isn't. I for one (1) would much prefer to be able to interpret the score attached to each comment as a measure of the LW community's opinion of that comment, which is badly broken when people do that, (2) don't make much use of total karma scores as a guide to a given LWer's general merit, and (3) would prefer a user's total karma score not to be strongly dependent on whether the people they've upset happen to be unscrupulous about breaking #1 for the sake of hurting that user's reputation. I think it unlikely that these preferences are very unusual.
The onus falls on the reader not to assign too much value to a comment or article's karmic value
Well, sure. But that's little reason for not trying to make the scores more meaningful rather than less.
I'm just tired of the signal pollution, and would like to be able to use karma to honestly appraise the worth of my articles and posts, without seeing 80% of my downvotes come in chunks that correspond precisely to how many posts I've made since the last massive downvote spree.
EDIT to add data points:
Spurious downvoting stopped soon after I named a particular individual (not ALL downvoting stopped, but the downvotes I got all seemed on-the-level.)
One block of potentially spurious downvoting occurred approximately one week ago, but then karma patterns returned to expected levels. I consider this block dubious, because it reasonably matches what I'd expect to see if someone noticed several of my posts together and disagreed with all of them, and did not match the usual pattern of starting with the earliest or latest post that I had made and downvoting everything (it downvoted all posts in a few threads, but not in other threads), so I'm just adding for completeness.
Spurious, indiscriminate downvoting started up again approximately half an hour ago on Sunday (12/1/2013), around noon MDT.
Edit: And now on Tuesday, 12/3/2013, at 10 AM, I'm watching my karma go down again... about 30 points so far.
Edit: And now on Saturday, 12/14/2013, at 2 PM, I'm watching my karma go down again... about 15 points so far, at a rate of about 1-2 points per second.