An Abuse of Copyright Claiming

From, http://www.marktwainproject.org/copyright.shtml,

In addition, texts edited by the Mark Twain Project and published by UC Press (such as, for example, the Project's 2003 edition of Adventures of Huckleberry Finn) are also protected, and may not be reproduced without permission.

I hope they know the mere slight editing, whether updating language, or punctuatorial, does not confer copyright on a work, but rather new substance must be added: a mere editorial reproduction of a work does not do this. If they've added annotations, for instance, these might be protected, but someone would need only strip them off.

And no, the justification for claims of copyright "well, it was costly for us", does not hold legal water. Thoughts? Corrections? Anyone?