You, me, or most of the people in this forum would come across one of those sites, see the AdSense, shake our heads and hit the back button.
Joe Average, who is searching for sites on "Platinum Cruises" (to use efv's example), clicks on a link and ends up at one of these sites of autogenerated keyword after keyword which makes no sense. Thinks to himself "geez, what kind of a site is this? Oh, wait, here's a link right to a site advertising Platinum Cruises on a Sterling Silver Budget" and he clicks. Why? He doesn't realize the site is being dodgy by doing what its doing, and he might not even realize the person who put up the nonsensical page is getting paid because he clicked.
And if this wasn't profitable to the publisher, you wouldn't see more and more publishers throwing up these kinds of sites for AdSense each and every day. I would be interested to have stats on what kind of clickthroughs these sites are generating, but I suspect they are probably higher than many would believe.