Im aware abt the south korean troop buildup, border clashes, that the peninsula being split in the first place was due to US meddling and the fascism, mass murders and rebellions in the south but im struggling to tie it together in a way that 1) fully makes sense 2) that id be able to explain to a normie without sounding like 
Also, if u have specific articles/sources abt the border clashes and general escalation from the south, id rly appreciate that 
I don't know much outside of the season of Blowback. The idea of NK being responsible has always been about "the first shot" — June 25, 1950. But...
"First shot" is a political construct. South Korea shot first by any reasonable definition. Jeju Island, April 1948 — 10,000 to 60,000 civilians and military personnel massacred by South Korean forces.
Responsibility is about causation, not timing. The US and South Korea created the conditions that made war inevitable. The 38th parallel was the US' idea. The US got in the way of every notion of peaceful resolution.
The standard narrative is propaganda. It was designed to justify US intervention, not to accurately describe the conflict's origin. The painting of NK as uniquely aggressive savages served the same purpose as the US declaring Native peoples savage — to dehumanize and justify violence.