Missile interception is not as yes/no as you might expect. If a rocket comes near enough to damage the target it may be counted as a hit without actually hitting anything. In combat it would explode and destroy its target, and during testing it may not have a warhead in it.
They were conducting tests. Tech people do a lot of that, and safety critical stuff gets tested a lot more, because it's safety critical. This involves seeing not just what works, but also what doesn't work. What were they testing? The accuracy of the flight path simulation? The sensitivity of the proximity sensors? The GPS in the rocket?
Also remember that rockets, warheads and airborne targets are not cheap. You don't destroy one unless you really have to.
If the rockets are experimental the designers and their customers may not want the press to report details of what they are doing, so competitors don't find out.
These days if the press starts going "useless rocket misses target" some uninformed government official might just cancel the program.