That seems to happen with a lot of communist countries.... although even the US has had it's share of them. The USS Vincennes incident comes to mind pretty easily. The circumstances were a little different in that they were under gunboat attack at the time.
Main problem is it was a senseless loss of life. IMHO overflights of any combat area should not be done by a transport provider for just that reason.
Yep, the SA-11 is a somewhat "advanced" system even for it's age (the BUK system originated around '79).. but with all the talk about them being supplied with weapons by Russia it probably should not have been un-expected. Even if they had acquired them from existing UA facilities - or something similar that Ukraine had since there were several military sites over-ran - they should have issued an advisory notice.
And I've always been a firm believer in the maxim "Expect the unexpected".