Dan,
The areas you're describing are neither bunkers nor hazards. Although the Ocean Course is very much a manufactured thing, the theory is that it consists of fairways and greens built in what's basically a vast sandy area with stands of native grasses and occasional water features. So just off the fairways are large areas with little or no grass but they are "through the green" in the same way as rough grass or woods would be on another course.
So the architect chose to create no "bunkers" per se and to let the sandy surroundings provide challenges to the golfers. Different challenges than constructed bunkers but legitimate challenges.
The only two valid critcisms of this arrangement, in my humble opinion, are these:
First, an argument could be made that conventionally designed and constructed bunkers result in a better playing field than the sandy areas at the Ocean Course. I see the the point but having played there I think the Ocean Course is as fun and challenging as any course would ever need to be and I disagree that it would be improved by hazards in the form of maintained bunkers. There are thousands of golf courses in the world with plain old bunkers but the Ocean Course is a different kind of course.
Second, one could argue that since the fairways are built above the original grade so as to capture drainage water and contain it to the course as a result the sandy areas are as much the result of the hand of man as any manufactured and maintained bunker. In other words, if you built it and it has sand in it then it much de jure be a bunker. My position is that any feature which is legitimate when naturally occurring is legitimate when manufactured by the hand of man but I suspect that is a minority opinion on this forum.
There are Rules of Golf specifying legal play from bunkers as well as giving a definition of "bunker" as a prepared area from which the earth is removed and replaced with sand. There is no Rule saying that any grassless spot of sandy soil must be surrounded by a boundary and maintained as a "bunker", nor should there be.