> Sometimes you'll make a controversial comment and you'll notice the score on every recent comment you made go down by one.
Sure, but that's a different phenomenon. If you make a comment that gets a lot of attention, sometimes people will go read a bunch of your other comments. I have also had the opposite of this happen, where I suddenly get upvotes on old comments.
Also I vaguely remember a couple of people here bragging that they had networks of sockpuppets specifically for mass-downvoting, but IDK.
This place can certainly be petty enough for that.