I acquiesce that because of the financial incentive, this [rank] should be limited. However, that's an issue that campaign managers should take care of: they should punish poor posting quality. And if they allow spam to manifest on the forum, then they themselves should be punished.
Managers are mostly responsible for such posting. For example, even yahoo, sylon and other worthy managers wants from their bounty members
20+ posts
per week. It's not easy to create 20 worthy posts. I don't mean a posts full of so-called "water" (big post with sense but without purpose and usefull information. About nothing in fact). Of course, if you spend most of your time at forum it will not be a problem. But most of "shitposters" have a real life and they isn't interesting in crypto, forum or other.
Bounty managers may decrease needed number of post at first. it will help to reduce the flow of low-informative post (do not confuse with low-quality posts)