You're throwing a lot of words that you don't understand nor have much relevance to the topic.

Before bilateral agreements and the freedom of movement, not Schengen which was ratified much later and is completely irrelevant here, you needed a work permit, not a visa (lowercase), which anyway at CERN is the equivalent of a diplomatic permit given to all international and tax-exempt NGOs in Geneva/Switzerland. And of course you lose your CDL permit quickly after your contract expires.

Getting a B permit before FoM would specifically not have been as hard for you as for someone from another continent.