Commercial use of Creative Commons tracks?

[Loving Linux Penguin]

Hey guys, sorry if this isn't the right place.

I'm a big creative commons fan, and in the past I have frequently used songs from sites like Jamendo for my videos on YouTube (which TECHNICALLY are not commercial). Now, if I understand correctly, a Creative Commons BY (Attribution) license means that you are supposed to be able to use the work for anything, even commercially, free of charge, as long as you attribute the artist. However, Jamendo says that commercial uses of music on their site requires a license from them. From their FAQ:

The track I want is published under a BY or BY-SA Creative Commons license: why do I need to purchase a Jamendo PRO license in that case?Creative Commons BY and BY-SA licenses signify that the artists are not opposed to the commercial use of their music. This doesn't mean they don't wish to be paid for it.

Does this not go against the very nature of Creative Commons? It sounds to me like a giant money-making scheme with some company trying to illegally make money off of people's tracks that are meant to be free. Is there anyone who can help me clear this up, and link to some reliable, neutral sources that clarify the information?

Thanks guys.

(oh, and feel free to edit out "Jamendo" if necessary, I wasn't sure if that would pose a problem with the TOS or not).