I think that arrogance is when a single vendor tries to single-handedly redefine open-source to fit their business needs better. Not just a license, but the definition itself.
A quote from the MongoDB CEO: "MongoDB was built by MongoDB. There was no prior art. We didn't open source it for help; we open sourced it as a freemium strategy". [1]
Whether the OSI was arrogant or not, I really don't want this person to define opensource.
[1]: https://techmonitor.ai/leadership/strategy/mongodb-ceo-inter...