I think it's quite bad form to publicly attack another company like this without discussing it in private first. I see no indication that there was any communication between 37Signals and GetSatisfaction prior to this very public post. I've had this kind of thing done to me before, and I think it's really out of order. Essentially, 37Signals have decided, in this case, to trade politeness and "being good" for making…
1) 37Signals have used their considerable influence to achieve change on behalf of many sites who have far less influence 2) 37Signals used the open model of putting pressure on a company publicly that GetSatisfaction have built their business on 3) They've effected change and created open discussion
Could they have been 'nicer'? Perhaps. But more effective, I'm not so sure...