Stansted is not in America. Thus, we do not shoot people that tresspass on it.
I agree, it was most inconvenient for some passengers and cost airlines some money but, as has already been pointed out, airlines don't have any "right" to make money that allows you to start shooting people.
They will go through the judicial system and probably be incarcerated for their crimes - which is fair enough; they broke the law. But I must admit, chaining yourself to an aircraft is a damm sight more effective than half hardheartedly waving placards at the perimeter fence...
Ps. I don't massively oppose deportations