Comment: I don't reach that conclusion

From the linked article:

"70 seconds after Norman shoots his pistol four times, the national guard command to shoot at unarmed students is given & Norman hightails it out of there into the arms of law enforcement & immediately hands over his gun."

I didn't see any indication here that the NG troops were under attack - the implication is that the students attacked the FBI informant, who may have been justified in firing at them in self-defense.

Over a minute later, the command was given to the NG to fire on the unarmed students. That's not self-defense, IMHO. My guess is, given the escalation of the situation, was that the NG commander heard the shots, thought he was under attack, and gave an order to fire on the students.

Why the FBI would arm an informant and send him amongst the students is still up for speculation.