The AOPA Press release states that the civil aircraft were within the MOA (under VFR, which is legal). The MOA was underneath the controlled airspace which one of the civil pilots climbed in to, without clearance, during his avoidance manouevre.
I think there are airmanship issues on both sides. The civil pilots should surely have expected to encounter military aircraft in high energy manouvres since the airspace was notified as active for military use. The military pilot was unwise in pushing home his interception closer than he needed to.
At the end of the day, if the civil pilots were 'VFR' and had the F16 visual, and the F16 came no closer than 600' (according to the USAF) why the drastic manouevres ??
You can read the various claims and counter claims here, along with various links to AvWeb articles and podcasts about the incident:
USAF F-16 Instructor Discusses Flying Into MOAs