OK, it was police who did the shooting. That was after, according to the FBI investigation cited in your linked article, bricks were thrown at the police by students of Jackson State and an officer was inured by debris thrown by a student, after which police armed with shotguns and other firearms INCLUDING machine guns fired (according to the FBI) 460 shots at a five story dormitory. Two students were killed and five or so injured. Two suicides by cop and five failed attempts.
Differences: It was police and not National Guard (distinction without a difference as to justification) and the gunfire was justified for the same reasons it was justified at Kent State.