The Ryanair plane didn't deliberately violate the airspace of Belarus in violation of withdrawn permission, they filed a flight plan to Vilnius just like they had every day for years and years. It was an airliner on a scheduled flight.

Your counterfactual involving a deliberate invasion of another country seems... extraordinarily weird. I mean, yes, countries defend their airspace when it's invaded by other nations in violation of established treaties. Duh. That is not what happened yesterday at all and you fucking know it. Stop this.