I think our Aussie bloke takes more care than is apparent. He is a very good herpetologist ....one of the best. And he knows which snakes he can 'muck' with and which ones are best left alone.
For example he can lift up the Australian Fierce snake and say it is the most venomous land snake in the world. And then he lifts it up and places it within striking distance of his face. To most that seems like an amazing thing to do but in actuality it is really calculated. The fierce snake is drop for drop the most venomous land snake (although many disagree which is the true no.1 heavy hitter), but it is not by far the most lethal. It is a pretty docile reptile that tends to run away rather than attack. The most lethal snake is the one that has potent venom, but also has a predisposition to strike hard and often. A fierce snake is extremely venomous, but it is only potentially dangerous. The most lethat snake is probably the fierce snake's African cousing, a fellow elapid, the black mamba.
Now, there was an episode where he was supposed to 'muck' with a Black Mamba. I remember ensuring i planned my work schedule so i could see that particular episode. Why? Because the Mamba is a 'requiem snake' ...serpentine death. Its venom may not be as potent as that of the fierce snake, but it is still over 65 times more potent than that of a Western Diamondback rattlesnake (and twice as deadly as a cobra). Herpetologist toxicologists say the Fierce snake is 80 times more venomous than a Western Diamondback, but as you can see the Mamba is no slouch. 65 times will kill you as easily as 80 times. However the Mamba has several attributes that easily put it over the Australian elapid. For one Mambas can reach lengths of 14 feet, they are highly aggressive when bothered (and single snakes have been known to kill multiple victims), they are the world's fastest snake (human beings can run faster than a mamba, but when you add undergrowth and bushes there is a chance the snake will nab you), and large specimens can rear themselves up to 6 feet off the ground (effectively being able to bite you in the face). A sight to see is the streamlined head of a mamba rising above 6 foot tall elephant grass and moving in absolute grace ....very hypnotic yet terribly 'wrong.' And these snakes strike fast and aggresively.
Hence when Steve Irwin faced off with the Mamba in Africa the guy was taking all the precautions possible. Dude was sweating bullets. Needless to say he did not try bringing the snake anywhere near him leave alone his face.
Hence many of these herpetologists like Irwin (and performers like the poor chap who bought the farm) know what they are dealing with. They know their snakes and they know how far they can push them and what they can get away with (unlike, sadly, many amateur wannabees who buy snakes from shops without knowing what they are getting themselves into). However the problem with the experts arises when they mistakenly push the envelop too far. I know a kid back home who was tagged by one of his pet snakes, a puff adder, and he died an excrutiatingly painful death (the venom of the puff adder is a cytotoxin/hemotoxin cocktail that effectively destroys your tissue and messes up your blood chemistry. Let's say it is an incredibly horrible way to die, both visually and in terms of pain. I'd personally take a mamba or cobra any day since death from a mamba is much faster, and the neurotoxic venom takes out the central nervous system hence making death virtually painless).
This dude probably thought he had everything in check. He dropped his guard when he shouldn't have and was tagged. The speed of death probably means he was tagged smack on or just adjacent to a blood vessel that made the spread of venom much faster.
And yes, no matter how careful Steve Irwin is what happened to this dude can easily happen to him. It actually might. For example he may decide to lift a normally docile Fierce snake and put it next to his face, and then light might be reflected off his camera man's video lens and the snake might panic and strike. A bite to the face is basically a one-way ticket to Valhalla!
This snake 'champion' basically rolled the dice as he had hundreds of times before. However these time he rolled snake eyes and got clocked out. Not everyone can be lucky all the time, especially when you are dealing with venomous snakes than only need to be lucky once.