Groupon suppresses negative feedback about businesses

I saw this deal today: http://www.groupon.com/deals/automotive-services-of-boston-1 and was struck that the business was only rated 3 stars on yelp: http://www.yelp.com/biz/automotive-services-of-boston-waltham Helpfully, Groupon shows snippets from the reviews: "Upon completion, the cars looked fantastic inside and out. Joe and his staff are friendly and professional" "The coffee stains that I thought would be a permanent fixture are gone." But, these reviews are clearly cherry-picked -- a third of the reviews are one star and are customer service horror stories. So I decided to post this on the comments page for the deal: http://www.groupon.com/deals/automotive-services-of-boston-1/posts After carefully composing and submitting a message, I was given a notice that "Thanks! Your post will be reviewed before it is published." It was never published. It'd be one thing if this was a 4.5 star establishment with a few grumbles, but Groupon is being pretty sketchy here.