These things happen. See the Korean Airlines 747 in September 1983. See the case of the USS Vincennes and Iran Air Flight 655 in July 1988. See Siberia Airlines Flight 1812 over the Black Sea in October 2001. These things happen, and they are highly likely to happen if you fly over a warzone.
Certain people who resemble teenagers still going on about last year's pop stars are determined to bang on about MH17. But what they are convinced is this matter of geopolitical significance is receiving less coverage than Harvey Weinstein.