I've engaged the task of trying to legitimize the presence of a listing of DRM standing for "Digital Restrictions Management" on Wikipedia's disambiguation page for the acronym DRM.
(This is a case where the original term stood for "Digital Rights Management", which is considered by the activist cause as whitewashing the true implications; as it may only limit/restrict and never grant any rights on the digital media to the users if the limitations were not present. It is advocated as a replacement meaning for the acronym by the Defective by Design movement.)
I'm not sure what to call an acronym with this character. The terms that came to mind were "parody", "backformation", or "re-purposing". Is there a more general term for taking an acronym that was marketed and understood as meaning one thing and promoting an alternate meaning?