The spammers would then use a different badge, for instance Informed (read the entire tour page), Organizer (retag a question), Supporter (first upvote), Teacher (first answer). It's an arms race, unfortunately, at least as long as there are low-effort badges.
We don't have a way currently to remove a specific badge but we do have a built-in way to remove a type of badge - by class (gold, silver, bronze). As such, I've just removed all bronze badges from appearing in the right sidebar "Recent badges" section to address this issue.
We're still looking at what we can do about the actual issue with the spam ...
The criteria are described exactly in What are the details on the "candidate score" which shows during an election?. Moreover, What would my Election Candidate score be? includes a link to a SEDE query that lets one compute their candidate score.