Whistle,
I think you're right up to a point. However, one other reason the Kent tragedy made its impression was because of those photos. Those grainy black and white pictures of the Guard firing in those freightening gas masks, that girl screaming over Jeff Miller's body, the pool of blood, the flag waving Alan Canfora in an open field, confronting the kneeling line of guardsmen with their weapons aimed, the white plumes of tear gas. Even today the power of those images is incredible, in the same way those images from the Edmund Pettis Bridge, or the children being firehosed in Selma still are.
To their credit, the groups that spent years trying to get the University to acknowlege the tragedy, to keep its memory alive, and to call into account those they felt were responsible, always made an effort to acknowlege the tragedy at Jackson State as equal to that at KSU. When they demonstrated, their principle chant was 'Long live the spirit of Kent and Jackson State'.