You have it backwards. The situation I'm describing is the opposite, coming from the assumption that they do want to release it. The poster I was responding to was the one who originally presented this idea by suggesting that the only thing getting in their way was the SGI rightsholders (currently HPE) who are forcing them NOT to release it. This is what is preventing whatever FOSS principles from taking place.

Now if this isn't actually the case and they're just using it as an excuse because they don't want to release it, and they want to continue playing this cat-and-mouse game with leakers and ROM sites forever, that's fine too, it's a little disappointing, but my intention is to present the idea that there is a different way.

Not "should be forced to"; rather "the cat is out of the bag, they've already been exposed to all the downside of open-sourcing, so now there's only upside."