Its really more a a continuous controlled explosion vs flying. Flying normally needs a wing of some sort, rockets have stabilizing wings but does not conform to Bernoulli's law (air moves faster over the top of the wing vs the bottom). It explodes when it stops becoming controlled. The way they make these things are pretty wild. When they are on the ground some of them leak a bit a fuel. When they blast off they heat up the metal expands and stops the leaks. It doesn't take a rocket scientist to understand how volatile the situation came become.
I have to guess there someone there saying its going to blow and everyone tells him he is wrong every time. Till well, it happens. There is always somebody that goes against the grain. They are proven wrong time and time again till there right.
So your more than a pretty face;-), i never realized it was oxygen! It makes a lot of sense due to the pressures. Liquid oxygen will violently expand if heated so they had to compensate some how.
You think there is something wrong with the rocket design that makes it vulnerable to explosion during refueling procedure?
They will look at the ridiculous amounts of data, come to conclusions from it and say, technically everything is fine. Then some bright spark comes along and says, but that just doesn't make sense. The data overrules them, and most of the time the data is correct, until they push the technology too far to meet deadlines or to increase revenue, by which time the bright spark has been shut up, and it goes with a vengeance. Heard a story about the Shuttle disaster, one of the engineers said something about physically standing in their way to stop them launching it he was so certain it would crash, obviously told to shut up and the rest is history. These people are preventative, it slows growth so no-one likes them but it also provides a sustainable foundation when things go wrong. You need perfection launching a rocket, it has to reach an escape velocity of 7miles per second, just because it's technically perfect doesn't mean that matey working on it didn't do something stupid! The more efficient an operation the more chance it will experience a fat-tail event. If you have a high efficiency company and their employees start to lose efficiency then they become distracted, and you end up with a concentrated set of fat-tail events. The question is, are Musk's companies starting such a trend because you can know they will not have the 'human' processes in place to offset them!
It could have been something as simple as a loose ground strap (ie a static electricy spark)......or something that could require an entire re-design of the upper portion of the vehicle. Tough to call right now. I wouldn't strap my ass to one for a few more years.....