The irony of participants applying
voluntarily for the campaign after reading all the details and then being "forced" to post in a certain board or comment on topics that he/she is not familiar with

It may be the money that is forcing participants and not the campaign.
Not money, greed. They shouldn't be joining such campaigns if it results in them posting very low quality posts just so that they don't get kicked out of the campaign.
To be fair I can't really blame
them for joining the campaigns. Before the recent changes you could get 0.004 BTC a day out of Cryptotalk's campaign. $32 a day ends up being $224 a week for a couple hours of shitposting a day. 11.6k USD a year is a very good salary in a lot of countries, and looking at the poor average quality of a lot of these posts I'm willing to wager that most of these people are not from English-speaking countries :')
The blame realistically needs to squarely fall on the shoulders of Yobit. I think it is still silly that a 300+ participant campaign has a single manager moderating it. It needs two, minimum.