While I appreciate your concerns and promotion of Freedom, I’m not sure about who the “we” mentioned in your post are. If you mean Ubuntu users then I seriously doubt they have a common goal “to advocate the use of free software”. If you mean Ubuntu developers or the Ubuntu project then I think equally a statement like:
by no means represents all of us. So while it might seem hypocritical to you to limit the usage of blog posts, such a blanket statement seems like a big simplification of reality. Indeed it would probably be hypocritical if you said it considering your advocacy. I, on the other hand have never supported the projects you mentioned and I have some concern about people/sites who use my writings simply for monetary gain. If I were to use CC-BY-NC licensing on my blog I don’t think it would in any way be hypocritical.
So, again thanks for the advocacy Rich, I feel it’s very important, but remember you aren’t everyone in Ubuntu or Planet Ubuntu either.