You can vote for a witness but do it via steemit not by clicking on a link left as a comment. If all those accounts are hacked this way I can't tell.
I only know for some reason many are Indonesian and the owner keys are taken.
An explaination can be that all keys were stolen during the hardfork and the hacker waited. There are many abandoned accounts but also not too active ones among them.
Mines were hacked in 2022, the only other explaination is the keys are stolen during the period steemit had all those issues a few months ago.
A hardfork can freeze everything, stop powering down. I wonder if this is an opportunity to steal keys as well. I remember we had no access 2 or 3 times this year.