The issue isn't necessarily with them for most people on here (though there are plenty who don't like them), it's with the claim that they were the sole contributor to the success of the season- essentially that they did more than what is likely true/accurate.
Yes, their being on the show, and making it to the end helped boost the numbers/ratings, but it is clear that they aren't the only source of the boost.
If they were the only source for ratings, the numbers should have stayed relatively consistent (if not steadily growing) throughout the season, even in spite of the changes in times, and with the squishing the second half of the season into consecutive 2-hour blocks, but it definitely didn't do that.
This doesn't detract that they worked well as a team, had the right combo of luck and skill to win, and are actually pretty nice, good people (who just play hardball in comps). Though they weren't my favorite team, they definitely grew on me.
But this is getting off topic- so let's just say that people who are popular in something else have a good chance of helping to add viewers to the season they're competing in, but another huge factor is whether that season gets a good time slot. They're not mutually exclusive factors in bringing in the numbers.