Kudos for not blaming the tool when that would have been the easiest route. It's worth mentioning that 10gen has MongoDB Monitoring Service out now. It makes monitoring MongoDB instances a lot more accessible and convenient.
That's not how everyone remembered it at the time, nor the picture the blog painted. And the mongo monitoring thing is much newer, right? Its like saying that a fire wasn't a big deal because next time there'll be a fire station.
Drawing a line between the difference in losing money for a paying service and a free service, while technically correct, is not the best business practice. Any online business looses money by being down, whether they can easily quantify it or not.