The whole thrust of the Brexit argument was to "take back control" and "to control who has the right to work in the UK". Once the UK Govt . indicated they really were going ahead it was clear that there was great risk that we would finish up where we are now. People warned on here several years ago that the CAA had no people or resources to do anything quickly and the Govt sure as hell weren't intending to provide them. The risks were clear and there was a way to protect yourself if you moved with any speed at all. It was also a certainty that the EU wouldn't continue licensing after a hard Brexit - legally they can't and there is zero political will or benefit for them to change things. Politicians mouthing off about "having or cake and eating it " only poured petrol on the flames.
Fairness doesn't cut much ice with lawyers I'm afraid. Pilots aren't the only sufferers either