The Massachusetts Open Data Initiative seems to provide only a link to the data, not the data itselfthemselves. Their terms of use couldn't be really applied here. The terms and conditions of the Massachusetts Archives website refer to the documents, not to their data collections.
data collector (a person or persons who actually collected the data);
author/creator/owner/principal investigator - it might be either the collector herself or an organization, e.g. government agency, university, research institute, which the collector has collected the data for;
data publisher (keeps the data and provides itthem for someone's use);
data distributor (it might be the same organization as publisher, but also might be another organization, say, with broader opportunities to disseminate information)
Now, the copyright always remains with the author/owner. And whatever other participants do, the data belongsbelong to the principal investigator.
Data provider/publisher shall comply with the owner's terms of use, especially regarding confidentiality.
Data distributor shall comply with the data publisher's terms of use, hence, automatically, with the owner's.
When someone looks for data, one should apply the terms of use attached to the data, whether they are written by the owner, publisher, or distributor. If the terms of use are missing or conflicting, one should apply the terms of use of the participant, which is one step higher on that list - publisher's instead of distributor's, or owner's instead of publisher's.
In this case, the data owner should be, in my understanding, the Massachusetts Registry of Vital Records and Statistics, the data publisher should be the Massachusetts Archives, and the Massachusetts Open Data Initiative goes as a distributor.
Can you download the data from the MODI? No. There is only a link, so forget about their terms of use. Can you get the data from the archives? Yes. OK, then you should comply with their terms of use. Specifically: not with the terms of use of their website but with the terms of use of their data collections under the Massachusetts law.
According to my experience, a possible citation for thisthese data might look something like this: Massachusetts Registry of Vital Records and Statistics, 2013, Vital Statistic Records (1841-1910). Boston, MA: Massachusetts Archives [distributor], though I'd hesitate to use it without contacting the archives.
What is the purpose of an Open Data directory if the collections it links to are not open data? Excellent question. Well, public records are open data, are they not? The fact that you should do some paperwork for the data publisher doesn't make thisthese data closed or private. But besidebesides this, I totally agree with you: the ultimate goal of any open data distributor should be to provide open data, not to complicate the whole process.
As discussed above, 2 out of 3 terms of use are not applicable here (one refers to a link, another to a website, but only the third one mentions the actual data).
Have to say, I really sympathize with you about what you are going through. (The archives didn't answer even to phone calls? What's that again, the government shutdown?) [1]: http://www.sec.state.ma.us/arc/arcres/residx.htm