Question

Which of the following best explains why there are different interpretations about historical events?

The main goal of history writers is to start debates.

They are written by people who have differing values and views.

Writers don't have access to the same primary source materials.

Second-hand accounts of events are not reliable and based only on opinions

Answer 1

"They are written by people who have differing values and views."
I think.

Answer 2

The answer the questioner is probably after is indeed that writers of history have different values and views.

But I don't think that's correct. I think most historians hold truth to be the absolute highest value, and if they all had enough information, they would actually mostly converge to similar opinions. In short, I don't think the average good historian is a slave to his emotions and prejudices -- his intellect is perfectly capable of winning out and giving an objective point of view -- but only if he has enough data.

Unfortunately, they almost never have enough data. So much of why people do what they do has to do with impressions and feelings that no one thinks to write down at the time. Why did Grant beat Lee at Appomattox? We point to things like the larger size of the Union Army -- but smaller armies have beaten larger many times, e.g. in the Mexican-American War, or the American Revolution. We point to the sophistication of the Union materiel, but of course the Vietcong drove the Americans out of Vietnam without helicopters and night-vision scopes, with little more than punji sticks and home-made bombs. So it's not nearly that simple.

Indeed, it's not unlikely there were a number of unquantifiable "in the air" factors that mattered: how the Union soldiers felt about Grant, and the Confederates felt about Lee. Maybe Grant smiled more genuinely at the regular troopers, while Lee had a haughty sneer. Maybe Grant had a nice commanding voice, while Lee spoke in squeaky Mickey Mouse tones, and ummed and errred a lot. Maybe the Southerners were discouraged fighting for slavery, maybe the North felt they were on the side of history, maybe the Union food was more nutritious, maybe the Southerners suffered more from bedbugs and lice, and on and on. If you actually lived during the time, you'd have access to all (or at least most) of these facts -- but you wouldn't be writing books analyzing the war, usually, since you and everyone around you had actually lived through it, and knew as much about it as you wanted to.

And by the time someone really wants to analyze the Civil War, because it has faded from living memory, all of these subtle human factors about what it was like to actually live during that time have vanished, because nobody thought to write them down at the time. You're left trying to piece the puzzle together with most of the pieces missing. Not surprisingly, with such a very limited supply of data, it's very easy to come to different conclusions.