Another thing i wonder is, why do bounty campaigns have posting requirements if the stuff that is posted is utter crap?
Because they don't care what's posted as long as it advertises the ICO or whatever is being promoted. That's the problem, which I'm sure you're now aware of. The projects don't care about bitcointalk, FB, Twitter, or any other website that they're using to hype their stuff. Basically they're just recruiting spammers, and they're cool with that.the rest is just general wondering why this actually goes on here when we all know the issues it creates? 
You answered this question here:I know that the bounties here are more than likely making up a large portion of website traffic.
And it pretty much sums up why spam is tolerated on bitcointalk. I've never been able to come up with a better reason. Any other forum would have put the kabosh on it long ago, along with the scammers and whatnot. I don't know how much Theymos et al make just having bitcointalk operating as it is, but I think it's a substantial sum of money. If Theymos did away with bounties and campaigns, this forum would be a ghost town, and it wouldn't be earning anywhere near as much.