What grudge is he even talking about? The lawsuits?
https://en.wikipedia.org/wiki/ZeniMax_v._Oculus
https://techcrunch.com/2017/03/09/oculus-cto-john-carmack-is...
https://en.wikipedia.org/wiki/ZeniMax_v._Oculus
https://techcrunch.com/2017/03/09/oculus-cto-john-carmack-is...
[0] https://store.nin.com/products/quake-vinyl
[1] https://twitter.com/ID_AA_Carmack/status/1306279981459308546