You are undoubtedly right that we all need to be careful and alert- and to err, if err we must, on the side of survival.
But the case of the 13 musicians seems to have been a case of overreaction on the part of some of the passengers, even if, as you say, some of the actions of the men were suspicious.
You need to know that the individuals in question were taken into custody and questioned on arrival in Los Angeles, as were several of the passengers.
You can be that the aircraft too was gone over with a careful eye. If these guys had left anything in the bathroom, as was intimated by at least one of the passengers, surely it would have been found.
But, what happened is this: the thirteen men established their credentials as musicians and went on their way.
Can musicians also be hijackers and terrorists? Surely that must be so. But it does not seem to have been the case here.
Please stop being reasonable and making sense. That's just not going to go over well tonight.
The passengers did not overreact. A group of men were behaving exactly as a group of terrorists might. They have the same culture and religion as jihadis. Dismissing their actions on the basis of their career isn't rational thought, it is delusion.
Can musicians also be hijackers and terrorists? Surely that must be so. But it does not seem to have been the case here.
What piece of evidence proves they aren't terrorists? It may very well be that they are not the terrorist team, but scouts for the team. No, they haven't done anything actionable, but blithely assuming they are just daisies because they didn't do anyting exactly illegal isn't all that smart either.
It doesn't matter what your day job is, if you start engaging in suspicious behavior on an airplane, you should be suspected.