That’s true Flybe used to fly EDI-BRU, NCL-BRU and BHX-BRU, although NCL and EDI have been dropped for the reasons you state.
However Flybe have just announced a new route starting in march from SOU-BRU to join the BHX-BRU route.
Hopefully no amount of illegal subsidies will affect that route as SNBrussels don't fly to Southampton.
And to think the rules that are being broken were actually concieved in Brussels.