Users in the forum, and participants in campaigns have to do their works well in order to help to build up good reputation for the forum, for companies that hire them with their signatures.
If the forum damaged by tons of shitposts due to signature, theymos will destroy all signatures.
If companies don't get benefits from their participants because shitposts don't catch attention of readers, and don't have effects for companies (adverse effects, in some cases); companies will stop running their campaigns after short time.
Some of those signature campaign managers do end up having to filter through a lot of bullshit, but it is likely NOT good to get too personally offended by it. You are correct that the incentives to join are not going to be too much, but if the signature campaign is paying in bitcoin, and the participant is just continuing to hold his payout, the amount of dollar value can really add up in the future, which will definitely inspire some folks to participate, especially from low income locations.
I still don't know why you decided like that, because you are obviously a strong poster, so you can keep posting, to clean up the forum, to help other forum users, and still receiving some bitcoins from reputable campaigns. Why not? If you want to give open slot for others, appreciated your kindness.
Pretty much I stopped participating in signature campaigns in early 2018 because I just did not want the ongoing hassle. I had acquired more than 3 bitcoins in about 2 years from the ones that I was in.. but still, when the BTC price went shooting up, I just began to think that my BTC holdings were way more valuable than trying to chase after more.. so that is kind of a personal choice based on circumstances.
I believe that in total, I was a part of 3 signature campaigns, and at first, I thought that it was so great to get paid for activities that I was already doing (posting that is), but after a while, the various hassles did not seem worth it to me, anymore... I felt that sometimes, I was worrying too much about getting paid properly and sometimes some of the controversy around some signature campaigns or even having to spend some additional time to follow some of the changes in the campaign or restrictions that they might impose regarding posting. The ones that I was in did not tend to have too many quantity posting restrictions, but I have seen that some current signature campaigns have those, too. But I think that the sum of the matter is that I just did not want anyone second-guessing the contents of appropriateness of any of my posts, and there does tend to be a bit of politics with any contractual relationship like that or even the impression that I might leave as if I am independent in my thinking or not.
I am not opposed to other members getting involved in signature campaigns because it can be a kind of easy money if you are going to be posting anyhow, then it might just work better for some of the other members as compared with how my own feelings about my involvement evolved.