Because America's enemies will not spend a single second analyzing what actually happened and will gleefully portray the video as a clear cut case of murder regardless of the facts.
Because America's Liberal media will do likewise if it suits their political agenda.
Words are the ideal medium for complex situations.
Photos and videos are the medium of communication for those who don't want to be bothered with thinking. They are therefore the red meat of hate propaganda.
When the Abu Grahib case was described in words, the news media yawned.
When the red meat of the Abu Grahib photos came out, the Liberal news media and America's enemies went into a propaganda blitz that nearly derailed the American war effort.
Oh, puh-leeze. They will portray the occupation of Iraq as a fascist imperialist bla bla bla war for oil regardless of what is or is not made known to the American people.