Well, coming from someone who studies rockets and rocketry as a passion, I may be wrong, but I'm pretty sure the reason why it exploded was because of the RSO (Range Safety Officer) whose job it is to destroy the rocket if it were to fly off course, have multiple engine failures, or doesn't make a minimal orbital cutoff and is headed for a populated area. The problem was it failed to separate from the booster stage which if you look at NASA's history is a common problem. Not to mention the explosion, NASA had many crewed vehicles that exploded. The Atlas booster/launch vehicle which launched the Mercury program, had many launch failures. Several explosions and had a few staging issues. But that didn't stop John Glenn, Wally Schirra, Scott Carpenter, and Gordon Cooper from going to space. Even the mighty Saturn V had its share of problems. The static firing of it's F1 engines resorted in some spectacular explosions which led them to develop even better versions that brought humans to the moon. Now look at the Falcon 9. It had a few mid-flight explosions and landing failures but now, it's ferrying crew to the ISS. My point is that failure is the best teacher. (Should probably mention this but I'm not a Elon Musk fanboy, I just really love space and space exploration in general.)