IP Issues with OOXML - Who's Afraid of the GPL?
Out of all the free and open source licences which are available, there are two which are disproportionately chosen by FOSS developers when licensing their software. Those two are the GPL and the LGPL. Of these, the GPL is disproportionately favoured over the LGPL.
If there are issues with GPL implementations then there are IP issues with OOXML. Any assurance that excludes implementation under these licences is just cause for the FOSS community to voice concern.
Imagine if you were standing next to someone’s land and there was a sign with the details of an open access promise (OAP), setting out when you are allowed to enter the land. It just so happens that the owner of the land is standing right beside you. You turn and say to them “So, this OAP, I’m here you can check me out, can I enter or not?”.