What is AtStake?

Many people are expressing surprise over the AtStake fiasco, firing of Dan Geer over a report (PDF) critical of Microsoft.  How can Microsoft or AtStake not behave that way when alternative is counter to survival instinct?

Of course, AtStake did not do Microsoft any favors by firing Dan.  All they did was confirm the concerns raised by the report: Microsoft can't help but be a bully even if it turned into a flower child overnight.  One doesn't have to be a bully for others to feel threatened.  It's like bringing a 800lb gorilla to a party and telling everyone to relax because it is so gentle.