It was pretty clear that Google never considered Honeycomb to be "complete". It was pushed out in a hurry to deal with the fact that manufacturers were pushing out terrible experiences on tablets using older Android versions. Honeycomb is merely a stop-gap to the next version (the upcoming ice-cream sandwich).
Google has been resistant to release the source precisely because I think they want to control (as much as possible) the proliferation of that code into devices that it can manage the bug fixing and release constraints on. That's why basically Google partners are the only ones with access to Honeycomb.
If the new version is released and the source code isn't, then I think RMS has a point. Ice cream sandwich better be "complete" and see a commiserate source-code push to go along with it. If not, Android has lost it's open source credibility. I think it is too early to make that call, however.
*disclaimer: I have no inside knowledge or any way to verify that my speculation is accurate:)