Lofted trajectories don't intercept as much atmosphere as a regular long-range flight however, so how such missiles would function on a proper long-range flight is anyone's guess. Also, the point of ICBM isn't to get the entire rocket to hit a specific point - that would be a failure. That's not how ICBMs really work.
The point is the multiple stages that detach outside the atmosphere, releasing re-entry vehicles which deliver a working nuclear device to the target, with the right working electronics to detonate it correctly (usually before it collides with the ground). If it just slams into the ground it probably won't detonate at all, that's been the experience of U.S. planes carrying nuclear bombs that have crashed or accidentally dropped bombs - none of them ever detonated, so just hitting the ground in the vicinity of your target isn't really all that likely to cause a proper nuclear detonation.
So we know that something hit the ocean at that particular point, and it was launched from North Korea. But we don't have any evidence that this was a properly detached and functional payload that could steer itself for re-entry, with heat shielding allowing the warhead detonation system to survive the trip back down, and then detonate a nuclear device, rather than just the spent stages of the rocket that went up, and continued in a parabolic arc.