SNAFUs and misunderstandings around open licensing seem to be more pervasive and persistent in the content realm than in software. No doubt this is partly because software is especially well suited to the concept, since it is both a textual expression and a practical tool, and the tool utility of free software offers a constant reminder of the value you gain from the free use of everybody else's contribution.
But another difference is that there was no Richard Stallman figure in open content. That is, someone brilliant, detail oriented and obsessive who was decades ahead of the curve on the issue. And capable of personally creating canonical practical examples of open content or educational resources. The equivalent would have been if an economics professor had come up with the full economic model of free and open source development as we understand it today, written the definitive text on the subject and freely licensed it, and written a full freely licensed text on IP law that was eventually adopted by many top law schools and almost all of the rest, and written an Econ 101 text book that was widely excerpted in the standard texts of many other major publishers.
And all that is well underway before almost anyone else is talking about the issue at all.
That is to say, the entire conversation for decades is on the very rigorous, if somewhat eccentric, terms laid out by one person. That's pretty much what happened in free software, and while everyone does not love Richard Stallman, the software world would be very different without his contributions. Without Stallman, I would have had to read a lot more blog posts by software developers who were upset about how their software was being redistributed.