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.
This is actually what makes it fairly easy for me to believe that Eugine is responsible. In discussions I've had with him in the past, he seems to downvote my comments automatically, without regard for content, merely because I am disagreeing with him. Take, for example, these two comments. Both of them are responses to Eugine, and both of them have exactly one downvote, which I am pretty confident comes from Eugine.
I can't see a legitimate reason for downvoting either of those comments. Neither one makes an argument or presents a controversial opinion. They are just presenting facts, facts which correct some misconception upthread. The fact that they were downvoted seems to me an indication of pretty significant mindkilling. Basically, the downvoter seems to be saying, "I don't want to see politically inconvenient facts on this website." Either that or, "I don't want to see people challenging my political views on this website." That kind of attitude seems quite compatible with indiscriminate bulk downvoting.