How can that be enforced though, I don't know much about stuff regarding merit farms but there are a lot of MS that have threads that they open to share your posts that you think is worth the merit and it just so happens that there are some people that's active on posting on those threads so no one can really blame them if they get chosen to get those merits.
Those threads are legit, you get merit if the OP of the threads thinks you should and that's okay. But there are threads which are just for farming, literally everyone merits everyone without worrying about the quality of the post or the actual thread/topic.
Maybe only thing that would help is more forum staff, but I don't know if that's possible.