Recently Shuttleworth, responding to some queries about an article on the Linux Weekly News website, told iTWire, among other things, that all copyright assignments empowered dual licensing and relicensing.
Kuhn, policy analyst and technology director at the SFLC, took exception to this, saying that what Intel, Canonical and other for-profit companies asked for were not the same things asked for by free software non-profit bodies like the Free Software Foundation.
The LWN article, by editor Jon Corbet, had expressed some reservations about the Canonical copyright assignment policy.
Kuhn, who was for five years a senior official at the Free Software Foundation before joining the SFLC, said there were two important differences between the FSF and for-profit companies when it came to copyright assignment.
"It's quite disingenuous for companies to point to the long standing tradition of copyright assignment to the FSF as a justification for their own practices. There are two key differences that people like Shuttleworth constantly gloss over or outright ignore," he said.
The FSF promised to never make its software proprietary and, secondly, as a non-profit it had a different duty to the public than a for-profit operation, he added.
"It seems that Mark Shuttleworth wants to confuse us about copyright assignment so we just start signing away our software," Kuhn said.
Kuhn added: "In essence, companies try to bank on the goodwill created by the FSF copyright assignment process over the years to convince developers to give up their rights under GPL and hand over their hard work for virtually nothing in return. We shouldn't give in."
He said he was not opposed to copyright assignment.
"...in fact, I support it in many cases. However, without assurances that otherwise copylefted software won't be relicensed as proprietary software, developers should treat a copyright assignment process with maximum scepticism.
"Furthermore, we should simply not tolerate attempts by for-profit companies to confuse the developer community by comparing as equals copyright assignment systems that are radically different in their intent, execution, and consequence."
Kuhn recently stopped using Ubuntu, the popular GNU/Linux distribution created by Canonical, in part because of the company's copyright assignment policies, and returned to using Debian GNU/Linux which had been his choice of distro until 2004.