Why no one is paying attention to the fact that the plane was flying over South China see which China is trying to claim for itself. Could it be the case that China by mistake shot the plane down ?
Impossible. The consequence of hiding the truth is an international shame. And do you really think any country launching a missile can go unnoticed? You know that area is under dispute and nearby countries are claiming ownership, meaning they are actively monitoring all military actions. There are satellites watching that area too. No. No.
And why China? I think this is more of an anti-China/China conspiracy. You got Philippines and Vietnam right over there. In fact, Vietnamese navy was the first appeared on the newspaper claiming it had detected a crash before the Chinese.
If anyone saw an airliner on their radar, they probably wouldn't even try to confirm what it was. If they saw an unidentified object, then they'd call someone.
It's not like the radar systems tracking these things on a day to day basis automatically classify something as a certain type or even size of aircraft.
Even if it were tracked by something, in that area of the world I bet there are quite a few "unscheduled" flights and it perhaps became something of routine. Or some remote radar operator is paid to look the other way on some flights, and mistook this for one of those.
Most likely is that it simply wasn't tracked by anyone who cared, and especially not by anyone who recorded the data.
From data so far it appears that no other country out there had any good radar system. That is why the airliner was not registered on any of those radar systems.