I think the quantity of posts have nothing to do with the quality of posts.
What I believe is that the conclusion you express does not follow from the premise.
At least in some cases, the quantity of posts does affect the quality. Someone who is a decent poster making 25 posts a week, if he enters a campaign like the one we are talking about and wants to reach the maximum payout, it is normal that on average his posts have less quality than when he makes 25.
Generic posts? I don't know for sure but I guess you do other things apart from writing in the forum, I don't know if it's a main job or what, but if you had no other job than writing in the forum couldn't you write more than 100 posts with decent quality? Normally you write more than 50, although some of them are updates of your threads.
You are right: you don't get it. Do you think that the target audience of that campaign needs quality to drive them to gamble in the casino?
What is said is not nearly as important as how many times advertising appears on the forum. I know you don't go there as much as I do, but I can assure you that the average user is quite mathematically illiterate, something you can check in threads that the same people who wear casino signatures, who are also customers of the casinos, open. Like:
1) They have tried the umpteenth variant of martingale and think it is bad luck that they have lost their money.
2) They create a thread regretting having lost too much money.
3) They naively believe that with bonuses and promos, the house gives them an RTP over 100, lol.
And things like that.
I understand stake have many participants to check but why best_change is paying such brilliant posters? These days you need to find something to earn merit, best way is to become a scam reported and report everything you find on the web, be in touch with other DT members and merit sources. One day you will be a legendary and the goal achieved to get paid $100 per week. Easy money, fake care for the forum.