For what it's worth, the StarTrekHistory.com domain is listed on whois.net as having existed since 12 August 2003--so that's over a decade.
I think the concern is that those who have collected these film clips for years (sometimes at great costs to these collectors in the case of rare clips) and then spend time and trouble and resources to have old scratched and faded clips restored have spent considerable amounts of money on their projects. These collectors probably don't complain about the costs; any hobby can become really, really expensive. But one thing these collectors have done over the years is they have made these expensive-to-obtain-and-restore clips available over the Internet--at no costs. The collectors are careful to not recoup any of their costs. The clips are made available to everyone for free.
If it's true that the pictures were simply harvested by an individual by trawling over the Internet, and then provided to the author and publisher of this book, and then money is being earned to some extent because of these pictures, I can understand the original collectors' frustrations at having been careful to bring in absolutely no money for so long, only to have someone come along and start monetizing those pictures.
Also, I think it's easy for the original collectors to have injected certain "tells" into their restorations. For example, they can simply crop each picture a tiny bit before they put them out on the Internet. "Look! The pictures from a completely 'independent' source has also cropped their images to the exact same degree and in the exact same way! How odd!"
Marc Cushman spent many years on this book. Long before Startrekhistory.com even existed. StarTrekhistory.com has yet to even prove that they are the rightful owners of the pictures, which they are not, and restoring of a picture does not give you any legal rights to said picture. If anyone owns a picture it is the "photographer". I am in the photo business and am very aware of copyright and what can and cannot be done. Star Trekhistory.com has no legal claim to any of the pictures used in the book. Most of the pictures used come from the private collection of Gurian. Now the original source of those pictures happens to be the same source that StarTrekhistory.com aquired their pictures.
I think it's funny how this whole argument has developed over pictures that are readily available anywhere on the net many time over and not the text of the book. The published text is what is important in this book and Cushman provides a bibliography of his sources at the back.
And to those of you throwing your accusatory stones out there have you ever downloaded anything off the web? Do you have downloaded copies of Star Trek episodes on your computer? or pictures? sound bytes? or anything Star Trek that you have not paid for? If so then quit your hypocrisy and clean up your own act before you go around making such damning claims. I bet everyone of you have illegal content in your possession! Probably did not think a thing about half the Trek stuff you bought at conventions that was "technically" illegal and yet you balk at a few measly, poorly reproduced, pictures in a book you have not ever seen or read. So in my humble opinion you have no opinion worth the effort it took for us to read it.