A bit of both. Wonder if they took one of those driving courses that advises you to watch leave room in front and watch you rear in case you need to avoid a non-stopping vehicle, though some initial critical thinking on the stopping distance for large rigs would have been good too!
Probably because they recovered from it, admitted they made a mistake, and posted it online for content. No point crucifying someone over a mistake that they (hopefully) learned from, especially when harm was avoided.