I think it's just the opposite. An air choke has a much greater chance of causing injury and would be somewhat irresponsible. Also, in a competition, guys are often entering with a combative attitude in which they have mentally prepared themselves not to tap out. It's stupid, but it happens.
It just seems reasonable to me that, intellectually, it would seem that a carotid choke would be more sensible for self defense. But practically, if your goal is to end an altercation, an air choke would likely deflate any resistance faster. I've put new guys to sleep before, because they just had no idea they were being choked. They were so comfortable, could still breath and just went night night.
One other thing to consider is that a blood choke has to be applied correctly to work, and against a person who doesn't want you to do it, that can be tricky. An air choke doesn't even have to work. Just the threat, along with the pressure on the adam's apple, is enough to get people to give up. It's a mental thing thing AND a physical thing.
Just to be clear, I am not saying that I am an expert. I don't go around choking people. What I am saying is that what drop bear suggests seems reasonable to me, based upon my own experience with both kinds of chokes.