Why is "American Civil War alternate histories" trending?

Wikipedia Overview

American Civil War alternate histories are alternate history fiction that focuses on the Civil War ending differently or not occurring. The American Civil War is a popular point of divergence in English-language alternate history fiction. The most common variants detail the victory and survival of the Confederate States. Less common variants include a Union victory under different circumstances from actual history, resulting in a different postwar situation; black American slaves freeing themselves by revolt without waiting for Lincoln's Emancipation Proclamation; a direct British and/or French intervention in the war; the survival of Lincoln during John Wilkes Booth's assassination attempt; a retelling of historical events with fantasy elements inserted; the Civil War never breaking out and a peaceful compromise being reached; and secret history tales. The point of divergence in such a story can be a "natural, realistic" event, such as one general making a different decision, or one sentry detecting an enemy invasion unlike in reality. It can also be an "unnatural" fantasy/science fiction plot device such as time travel, which usually takes the form of someone bringing modern weapons or hindsight knowledge into the past. Still another related variant is a scenario of a Civil War that breaks out at a different time from 1861 and under different circumstances.