I was a history major (B.A. History, University of New Orleans). Some of your points are well-taken. I realize that some of the incidents did not involve federal troops, but they were troops, nonetheless (and subject to federalization if called upon in that regard). But as for Kent State, even the National Guard officers commanding later testified that the Guard was in no immediate danger, and that in fact most of the students were 300-400 yards away. Oh, you had some students throwing tear gas cansiters back at the troops, but they landed much too far away to constitute any real threat. Kent State happened because a Guardsman got trigger happy, and started something that never should have occurred. Immediately the shots were fired all the officers and NCOs began ordering a cease fire, and were not subtle about it.
I still think the context of Kent State is often overlooked. As I recall, the ROTC building had been torched the night before. Also, there had been widespread looting, window breaking, and drinking in the town.
I remember seeing some home film, taken by a student in a dorm or apartment. It shows the Guard on the top of the hill, with hundreds of students headed their way, up the hill and out of nearby buildings. The situation looked provocative, and the events of the previous 24 hours did not help things. And, as you point out, there was a breakdown in command.
Nevertheless, I don't think that the Kent State incident is a good example of the Federal Government using military force against the population.