[ctdonath]

I often see the same pattern in both directions on hot-button topics. There's a burst of short comments from those more emotionally for/against something, with the total score absolute value (up/down voting) becoming large enough to get the attention of the greater number of more thoughtful opposing-view people who aren't so wound up about it upvote & write longer comments, first to counteract the initial burst, and then to support the growing number of thoughtful responses.

I've seen it many times on my own posts: might get a -2 shortly after posting, but then +10 or so about an hour later. (Seems I often push buttons others agree need pushing.)

[m3rc]

doesn't "pushing buttons others agree need pushing" just mean "participating in an echo chamber"?

[ctdonath]

No. There may be a broad range of participants; sometimes those holding one view may stay quiet about it, but then find reason to rally behind someone promoting/defending it.