Remember the RMS Lusitania

Go back about 99 years and you'll learn that destroying a transport laden with passengers, no matter what justification is claimed by those who did the deed, is a very bad move.

The Germans may have been justified in sinking the ship, but they badly lost the subsequent propaganda battle. The British were able to successfully paint the German U-boats as the wanton murderers of women and children.

When outrages such as the sinking of the Lusitania or the downing of MH Flight 17 happen, it can be difficult to separate out fact from propaganda. All sides have reasons to fudge the details, if not outright lie. Everyone involved calculates that the effects of being found out of having lied will occur long after they've harvested the maximum benefit from the tragedy.