I'll give an example. I work in an office building with many floors that have exact same layout. One day I was on a floor that wasn't mine, and went to where my desk should be, and tried to sit down. I was shocked, for a moment, to discover my coworkers had all been replaced by strangers. In this case, I made an absentminded mistake of not paying enough attention to my current location - but the consequences were trivial, so the mistake itself is no big deal. Now, on the other hand, suppose while driving down the road, I absentmindedly ignore a red light, plow through an intersection, and kill a family of five. This is also an absent minded mistake, but the predictable consequences of being absent minded while driving are a lot more extreme than being absent minded while walking about an office building.
To apply the logic of my example to the case at hand - imagine that in one scenario an employee is, during a boring moment, cleaning his keyboard with his chat application open. This results in that employee sending a nonsense message to a coworker. Silly mistake, and no big deal. Now, suppose that same employee has the "Missile Alert" app open and decides to clean their keyboard. This is a similar mistake, but with potentially bigger consequences. I think it's fair to treat these two actions differently.
Of course, the circumstances affect what the reasonable standard of care is. Oopsies by ship captains, surgeons, and even drivers are held to a different standard than me making a typo on some random thing I'm writing or a simple program.
In your example, running a red light is commonly taken as one of those things you just don't screw up on (and that can't be eliminated through automation at this time).