Vivaldi has a post on their blog regarding this.

Waiting for Firefox to implement native browser profile switching UI (not container tabs, not desktop shortcuts, not janky workarounds/hacks) and I’ll be there full time.

I think this is similar to how reddit sorted before r/The_Donald memed its frontpage. It’ll probably settle down as people are still figuring things out but for now, I just temporarily block !lemmyshitpost@lemmy.world and !196@lemmy.blahaj.zone so I can view other posts.