Merit abusers should be tagged, I support the idea to fight against massive abusements from account farmers (in some cases after merit system launched have been changed to merit farmers).
I would gladly tag merit abusers, but as I've said before it appears Theymos doesn't want that, and I have to respect his stance.
However, in some specific cases and in somewhat extents, making final judgements on whether two or more accounts exchanging merits together over several rounds should be taken as objective as possible, and in some cases, it's really hard to find if abusers make their deals smart and clever.
Also, these cases of abuse are much less clear to me than account sales or even campaign cheating. There definitely can be users who really like what one particular person has to say, and I might tag such a person unnecessarily. I don't feel like dealing with the backlash of that, nor do I really want to neg someone and be totally wrong.
In my opinion, shit-posters will be eliminated somehow, might be due to side-effects of merit system. With current rules of the forum on campaigns, lower ranked users (below Member rank) still have opportunities to join, hence they will definitely keep spamming the forum. However, some of them will have strong desire to rank up. Consequently, they have to be more constructive, try to be more constructive, over time they will automatically changed to be real constructive users. That's one of the most magic impacts of merit system on the forum users.
This all will take care of itself eventually; I have some faith that this'll be true. We're only in month 2 of the merit system, so it's still young. It wasn't designed to stamp out shitposters immediately--it's a gradual, long-term thing I think. We'll see in a year or two.
Lastly, I hope that Theymos will put stricter rules on pre-requisites to join campaigns in the forum. When new stricter rules implemented, I believe that spammers will be wipen out on massive scale and faster than simply base on merit system.