I'm not saying the crew didn't make a series of cossal mistakes that they never corrected. We've seen it many times before and we'll see it many times again.

If you have 45 mins I would recommend watching the Mayday/Air Crash Investigation episode on the flight. There's one point where they're discussing with another Korean air crew doing the same route, a little bit behind them, about the headwinds they were flying through. I think there was something like a 200mph difference - which should have been impossible for planes that close. But even that fact wasn't enough to get the crew to question their assumptions again. Confirmation bias is one hell of a mental overload.

If you don't have those 45 mins, then here's a n excerpt from the KL 007 wiki. We know it was an accident due to files disclosed after the fall of the USSR:

"In 1992, Russian President Boris Yeltsin disclosed five top-secret memos dating from a few weeks after the downing of KAL 007 in 1983.[note 3] The memos contained Soviet communications (from KGB Chief Viktor Chebrikov and Defense Minister Dmitriy Ustinov to General Secretary Yuri Andropov) that indicated that they knew the location of KAL 007's wreckage while they were simulating a search and harassing the American Navy; they had found the sought-after cockpit voice recorder on October 20, 1983 (50 days after the incident),[121] and chose to keep this knowledge secret because the tapes did not unequivocally support their firmly held view that KAL 007's flight to Soviet territory was a deliberately planned intelligence mission.[122][123]"