What was the scale of your community, and how long did the forum last? I would be curious to hear such a system would perform against large numbers of bots or sockpuppet accounts. I think that techniques that work in forums may simply not scale to millions of users, when it actively affects the national conversation.
For example: every time a big political announcement is to be made or an event happens, the optimal game theoretic play is to ban them to prevent them from being able to set the narrative. And it just takes one person to do it. That's not hard at all: if you have millions of users, someone will do it!
I ran it for about 6 months iirc. It never got to the size where sockpuppets were a legitimate threat or IP bans insufficient. Occasionally people would switch wifi to ban the person who banned them, but I leveraged cookies where I could to try to detect that behavior. This was before browser fingerprinting and "evercookies" were widespread, or I probably would have used those too.
In your example, the person would have to have posted recently in order for you to ban them, since bans only worked on quasi-recent posts. But yes, if you made yourself into a target, someone would ban you, and it was accepted in the culture because it was fun. It was acceptable that everyone got banned frequently, but far less frequently than the trolls. I should probably have mentioned that all users were anonymous to each other.
For example: every time a big political announcement is to be made or an event happens, the optimal game theoretic play is to ban them to prevent them from being able to set the narrative. And it just takes one person to do it. That's not hard at all: if you have millions of users, someone will do it!