I will say, the length of the videos isn't off-putting to me. There's a person I watch on YouTube named Fredrik Knudsen. He has a series called Down the Rabbit Hole, and his videos tend to range from 30 minutes at the shortest end to, IIRC, 2 and a half hours on the longest video. He does that because he felt his efforts to cut down on earlier subjects tended to give his videos too much of a "Cliff Notes summary" feel, rather than the entire picture. I can respect that.
My issue is with Destiny's delivery. As noted in the OP, Destiny can come off as a dick, which makes watching him for literally hours not quite work for me. In addition, there is a difference between what Knudsen does (essentially, a full retelling of a scene/person) and what Destiny is doing here (an investigation into a specific incident)). If you can watch a half-hour (minus commercials) program and learn enough about an incident to know what they are talking about, and an hour-long program (minus commercials) can cover a documentary program with interviews, why make these videos 2-3 hours without commercials?