They employ a lot of people directly, and a lot of people are employed in their ecosystem. I'd deny that this is exclusively for MS, though. Every large company has an army of employees that come in to explain how things actually are. On HN, this happens just as often for every medium-sized company; the only companies who absolutely get bulldozed when they do something worth getting bulldozed for are tiny, because their defenses just get shouted down by the employees of competitors.