This pretty much nails it. The "politics" angle has been revealed to be a red herring by the subsequent accounts of everyone involved. The same contentious discussions would have happened had this policy already existed! I guess you could say the policy gives the founders a ban hammer to swing to end discussions they don't like.

Separated from their justification, the 6 policies represent an assertion that Basecamp leadership are the sole arbiters of all things Basecamp. I don't think that's an awful thing in itself, but the way it was announced was clearly felt to be completely demoralizing for employees who assumed their judgment on the direction of the company was valued.

And the result seems likely to be catastrophic. Basecamp has had their pick of the litter for talent for years. Sure, they'll hire new folks who are aligned with their new way of running the company, but you don't go back to being a beacon of the industry when you lose 1/3 of your staff in a week over an ego trip.