[darose]

From the Vanity Fair article, it sounds like Goldman is in fact violating the terms of the license, but not in the way you're describing. (I.e., not by refusing to release changes.)

According to the article Goldman would routinely strip off the license/copyright from off of the open source code file and replace it with their own copyright. And that is a violation of many open source licenses.

[yummyfajitas]

I could be wrong, but wouldn't it only be a violation to release the code after stripping off the license/copyright?

[No1]

Whoever modified the copyright headers then redistributes the files internally to other programmers and systems. You cannot modify a copyright to your liking and redistribute the work.