It's impossible to delete an account by forum moderator. They can just ban a user. I think merit abuse is not on the list of crime that punishable by ban? I found some merit abuse thread such as giveaway of merit for every correct answer for trivia question.
Maybe in your point of view, the giveaway of merit for answering questions is a form merit abuse but for most of us, it is not. Actually, it is a great way to motivate other shitposter/spammers to put in a lot of effort and thought in their posts knowing that they will surely get a merit assuming they answer the question correctly. Moreover, they will understand the topic they researched on and will help them to contribute even better in the forum.