While searching for information for a course I'm teaching, I ran into this article from the US Department of the Interior describing some archaeological sites in the Southwest. It has tons of blacked out text. It doesn't seem to serve the purpose of correcting mistakes, as lots of details from the article are hidden. Is this a form of censorship of the information? If so, why would the US DOI have a reason for censoring this information?
The gps coordinates or other similar information is withheld for some sensitive archeological sites to try to minimize vandalism and other issues such as unauthorized "collectors". For example, there is a prehistoric rock quarry not too far from me in New York State, whose exact location is not published.
This seems to be the situation in the paper you cite. Some sites are culturally sensitive. Some are scientifically important. In the age of four wheel off-road vehicles it is too easy to find, contaminate, and even destroy such sites.
Yes, this is a form of censorship. However, it is well motivated and is meant to protect important cultural resources. It is likely that most of the information which has been redacted is related to the location of archaeological resources. As Buffy suggests, this is done primarily to prevent unauthorized collection—a quick look at eBay should convince you that, for example, Puebloan pottery can sell for hundreds (or even thousands) of dollars.
It may also be worth noting that, while these kinds of documents are produced for the use of Federal land management agencies, they are not, in general, subject to Freedom of Information Act (FOIA) requests. In fact, information regarding archaeological sites is specifically exempted in FOIA. Further information may be found on the websites of the Advisory Council on Historic Preservation (the Federal agency responsible for administering resources of historic significance) and the Department of Justice.
The above discussion concerns archaeological records which are kept by Federal agencies (the most significant of these (in the West, anyway) being the DOI Park Service, the DOI Bureau of Land Management, and the USDA Forest Service). Federal agencies are not the only organizations which conduct archaeological research or keep archaeological records. State agencies (either directly, or though publicly funded universities and colleges), local/municipal agencies, tribal agencies, and various private concerns (private colleges and universities, landowners, archaeological contractors, etc) may also keep records. These kinds of records are subject to patchwork of laws and regulations, and may be more or less difficult to obtain, and may be subject to greater or lesser "sunshine" requirements—it is common to exempt archaeological records from such requirements. Moreover, private landowners and tribal agencies, which are generally not subject to the same kinds of sunshine laws, may be very reluctant to share information, and likely have no requirement to do so.
The question indicates that this is for a course that the asker is teaching, hence it is unlikely that they really need access to the redacted information. However, the redacted information can almost certainly be obtained by legitimate researchers with a little bit of legwork. For example, if a researcher is planning on doing limited, non-destructive field work in the area, a couple of polite phone calls to the archaeologists at the appropriate land management agencies (in the case of the records described in the question, the Lincoln National Forest may be an appropriate place to start) may yield the information, and perhaps an invitation to tour the area.
For more intensive work (e.g. if excavation is involved, or if students are coming along), the walls are a little higher, but it again starts with phone calls and email. As is true with most things, personal relationships matter. If you really need the access, build trust with folk, and they will almost certainly help you to open doors and get through red tape.