I don`t think that the merit-system somehow discourages and blocks the way to shitposting. Rather, it`s a kind of an obstacle to getting money for spam (although this is a hurdle in the form of one merit, unfortunately, you can easily get around). After all, the merit system doesn`t prohibit writing bad posts. Even if you remain a newbie, you can still spam and write low-quality comments. But you cannot wear a signature and participate in bounty campaigns. Therefore, the merit-system reduces the chances of earning money and the scale of these incomes, but not the opportunity to write shitposts.

That`s why I`m more inclined to think that merits encourage the writing of better comments. At the very least, they become a way to rise in rank (what most forum participants want). What are the motives of the members, who strive to earn merit, is another question. But at least they try to write more constructive posts.