I don't think these comments deserve downvotes, and normally it's unlikely to get three consecutive "-8"'s (several days ago there was no downvote). So my conclusion is that some toxic users just gathered here and deliberately downvoted things. Maybe it is this post attracting them.

I don't care about contributions now, but I want to let everyone know this disgusting conduct. Also I think for the website it's good to show who did upvotes/downvotes. Life is not only about algorithms, but also about how to respect others (even when you are anonymous).

[Update] It seems that high-rated users have high-weights. This might make sense on algorithm discussions.

It’s not a big issue. But several days ago my contribution score was positive, and today I suddenly found it became -16. I didn’t post any new things in recent days (except for this one).

So did Codeforces change its way to calculate the contribution scores in recent days?

Or someone was deliberately trying to gather many users to downvote my comments (I don’t think this is likely because I didn’t see any obvious changes to my previous comments’ voting). (Update: it seems that the number of downvotes won’t show if it’s small, so it could be the case that someone just downvoted all of my comments, and this is disgusting.)

Or does Codeforces have a complain system so someone else just reported my account (with no reasonable reason)?

Update: it is still changing after I posted this post.