I got the information from @logic that these users are part of a botnet. So far, 17,462 related accounts have been found.

Hopefully, the Hivewatchers team can tag these botnet users as soon as they post, so that it will be easier to determine which users are bad guys.

For us community members, preventing them from getting benefits is what we can do at the moment. Making them return empty-handed will naturally solve the problem.