I am surprised that Microsoft took as much flak for it as it did when pretty much every other online property including Google and Facebook has complied with these demand (as they are legally supposed to do).
Besides it is also interesting to note that providers such as Google and Facebook probably have a lot more interesting data that the government is likely interested in. It is more likely that data from the likes of Google and Facebook that can be used to track an individual or can be detrimental to them as compared to the data that Microsoft has.
Microsoft has gotten the worst of it so far because of NSA documents explicitly describing the relationship with Microsoft. Presumably similar documents exist for the other companies involved, but they haven't been leaked.
Besides it is also interesting to note that providers such as Google and Facebook probably have a lot more interesting data that the government is likely interested in. It is more likely that data from the likes of Google and Facebook that can be used to track an individual or can be detrimental to them as compared to the data that Microsoft has.