This looks weird to me.

• Kbin downvotes are public, you can see who made them at kbin.social/u/@artifice@lemmy.world. Kbin doesn’t federate downvotes from Lemmy though, so you can only see downvotes made there. I stalked your profile a bit on kbin and there was nothing weird. Mostly no downvotes, and in the few cases there were some there was no correlation of people across threads. The worst I saw was like three people downvoting a series of comments in a single thread, which is not weird or stalky.
• Downvotes are not anonymous to Lemmy instance admins though. They are recorded in Lemmy’s DB with a link to who made them.

I would consider reporting this to info@mastodon.world. If someone is actually sockpuppeting 10-20 accounts and profile stalking, that sounds to me like bannable abuse and something the admins might be interested in looking into. Now, of course, if you’re the one who has been harassing people in old comments, moderated comments, deleted comments, or DMs… admins might decide to ban you all. Two wrongs don’t make a right, and often result in two bans. It’s also possible that admins have bigger fish to fry and won’t have time to investigate… but if I were admin I’d be interested in early instances of mass-sockpuppeting so I could think about ways to detect and react to it.