A little bit of an interaction that connected to the signature campaign would be acceptable, but if it would be 1-2 pages of posts coming from different users with regards to a single problem isn't because like you said, it would create a mess towards the whole thread.
However, the campaign manager could do things to prevent it:
1. Make it self-moderated. I don't see any reason for the campaign managers to delete application, but in deleting some posts that would clog the overall thread is.
2. The campaign manager themselves will say to not interact on that thread anymore. Making a post with regards to this one will take a minute or 2 for the campaign manager, and for sure, all will stop after that.
With regards to what happened with Betfury signature thread campaign, well I also shared my opinion with regards to one concern, but that's it. At the end of the day, the manager will make their own rules, and we will follow it like what most are saying.