Missile defense exists in a world of its own. It has a special budget process that exempts it from most congressional oversight, and it is pioneering a new acquisitions process that redefines the very nature of what constitutes a "threat." The system has a separate definition to denote what it means for a weapon to "work" and even what it means to "know" something to be true. The shield operates beyond the world of empirical testing, and outside the four service branches of the U.S. military.I recommend reading the whole article, and Brendan's blog post, both linked above.
Ignoring this one result, for the moment, there is nothing in the test record that provides any degree of confidence in the GMD - none. All of the "successes" are at best, technical successes - that is they indicate some benchmark has been reached; or they're dumbed down demonstrations that something can be hit with something else, disregarding the important consideration that the ballistic properties of the target don't bear any resemblance to those of an actual target. Another factor ignored is the existence of realistic decoys - the only decoy tests listed used a small number of balloons to simulate the existence of decoy warheads. These are important benchmarks, to be sure; but, the ability to distinguish a lighter than air, comparatively slow moving soft target, from a missile warhead traveling at supersonic speeds does not provide any sort of real world confirmation of an anti missile system.
I don't see any reason to believe that the FTG-05 result provides any reason for greater confidence, based on what has so far been published.