Same thing happened on 9/11 - US chose do land all aircrafts, and in case that anyone disobeyed orders it would be promptly shot down - foreign planes or not, it didn't matter in slightest.
Second: they let the plane in on a flight plan that clearly took it to Vilnius. Again, that's false pretenses.
Per the analogy above: consider a consulate telling someone "sure, you can board this plane without your passport, it's fine" and then arresting the person for a visa violation on landing.
Looks like they learned from the best.
Yeah, this is trolling.
A major international incident (the head of state of one nation violating the airspace of another) that completely and utterly dwarfs whatever nonsense was going on with Snowden. I know it's hard for geeks here to understand, but Snowden just isn't that important.
Again: he wasn't even on the plane. And Morales apparently had no intention of putting him on there. He was just pissed off that no one trusted him about that.
The Ryanair plane didn't deliberately violate the airspace of Belarus in violation of withdrawn permission, they filed a flight plan to Vilnius just like they had every day for years and years.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.
Denying Morale's plane permission was an act of diplomacy, albeit a very uncommon one and one in pursuit of an unjust goal.
Forcing down a foreign airplane on an international flight to arrest someone on it is an act of war. Sorry.