I see your point:
You don't tug on superman's cape
You don't spit into the wind
You don't pull the mask off that old lone ranger
And you don't mess around with heavily armed, fanatic murdering scum bent on martyrdom.

But I disagree with you from two directions. First, they had been bombed before and knew the seriousness of what they were doing. Second, there was a police guard responsible for protecting them from further assaults who did not do their job.