The reason is explained by The Memory Hole here:
The Congressional Research Service, a branch of the Library of Congress, provides fact-rich, unbiased, nontechnical reports to members of Congress regarding a variety of issues. The CRS does not distribute these reports to the public in any way. You can't get them online, order paper copies from the CRS, or even read them in the Library of Congress. CRS is not subject to the Freedom of Information Act. The Service's philosophy is that it works for Congress, not the people, so its publications are deliberately made difficult to get.We're not talking here about material that is kept from the public due to national security concerns. CRS produces non-partisan analyses of issues before Congress. In fact, the information is not secret at all, it is merely difficult to access. Apparently, these hurdles to access are created intentionally by the CRS.
A few exceptions exist. Some third parties get selected reports through Congressional representatives, then post them online. The State Department's Website contains CRS reports that State prepared. Penny Hill Press provides all CRS reports, but you have to cough up $29.95 for each report if you're not a subscriber ($7.95 is you are a $299-per-year subscriber).
For a while, the Websites of Congressmen Mark Green and Christopher Shays provided a gateway to a CRS internal database, giving us access to a large but still incomplete selection of these reports. (Frustratingly, the CRS database blocked search engines, meaning that the reports never showed up in searches and weren't cached by Google or Gigablast.)
In mid-October, Green and Shays suddenly shut off access. Since theirs were the only doors into the CRS database, all of us lost access to this rich source of information. Luckily, The Memory Hole had copied many of these reports before the curtain came down. Below you will find the four main pages from Green's portal to the CRS database. If The Memory Hole has a copy of any given report, the link "MemHole mirror" appears after the title. We're interested in filling the gaps, so if you have a report that's listed but not mirrored, please send it. And we're especially interested in receiving CRS reports that don't appear anywhere else online.
For more info on access issues surrounding CRS publications, read "Congressional Research Service Products: Taxpayers Should Have Easy Access" from the Project on Government Oversight.
Blogs benefit public discourse by widely broadcasting information and opinion. They have natural limitations (e.g., the limitations on the time that bloggers can devoted to any one posting, for instance) and, as a result, blogs often offer secondary comment to more in-depth analyses. Organizations and institutions such as CRS are intended to produce studies that are easily digestible (that is, they're easy to read), yet offer a good degree of depth. The CRS should unlock access to these reports and allow its database to be available on the Web and searchable via the major search engines.