They should at least take down the page on request.
GS has every right to create a forum where customers can air grievances. They should add links to the official support forum, and throw in a couple more "unofficial"s in there as well. But beyond that, they don't have an obligation to take down the whole forum. That's extreme.
The really sad part is: GS is easy to confuse with 37 signals, because they are both minimalist and elegant web sites. It's the high polish that adds to confusion.
GS should go the extra-mile to avoid confusion, but let's not lose our heads here.
Edit: It's been pointed out that I was using "DMCA request" incorrectly. I replaced it with "cease and desist."
No, don't confuse the issue. Copyright and trademark are not the same. (And are distinct from patents and trade secrets, for that matter.)
The DMCA is about copyright. None of the posts on GS violate copyright. [1] And, if one does, a DMCA notice can be used to take it down, but not to take the whole site down.
This GS incident is (or would be, if and when lawyers enter the picture) a trademark dispute. GS stands accused of misusing other companies' trademarks in a way that creates customer confusion: Customers see a trademarked logo and a trademarked name on the GS pages, and are misled into thinking they are visiting a site that is officially associated with the trademark holder.
You can say any damn thing about Comcast you want. [2] And I believe you can even use Comcast's trademarks in the process, so long as you do so for the purpose of commentary (and not, say, to compete with Comcast in the cable business), and so long as there isn't evidence that you're misleading people into thinking that your site is officially associated with Comcast.
P.S. I am not a lawyer. Though sometimes I wish I were. I certainly spend enough time talking about IP law.
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[1] Well, very few, anyway. Obviously anyone could put up posts on GS that violated copyright.
[2] Well, okay, anything that you honestly believe is true. You're not allowed to defame them.
Yes. They have no right to make it look like they represent the company in question, though. GS's defense is that they mostly do represent such companies...and yet they use the same setup for companies that may not even know their site exists.
Consumer-grievance forums have been around for years. They don't impersonate companies.