So you are saying i should accept all the spammers?
No. I have not even remotely implied that.
Who is posting crap, what should i do to them?
Kick them from the campaign after review.
Ok, I will delete that rule, BUT will permanently reject all those participants who didn't follow this already mentioned rules
3: Posts must be constructive and On-topic. Spamming, low-quality posts, copy paste and off topic, posts will not be counted.
Again, what you fail to understand is that: You can make such modifications but
for new participants. The existing ones should be treated according to the ruleset which they signed up with. Additionally, you could add a transition period where they would get paid for 1 round (if applicable) and would need to adhere to the changed rules for the following round. However, I do not believe that said campaign will run for too long thus I don't see this being a possibility (unless you have a weekly payout or something).