Simply put, because of the unique challenge of keeping venomous in captivity, as well as a fascination of their unique beauty and abilities.
Venomous snakes are the most highly evolved of the snakes, and their unique ability to subdue prey with venom makes them efficient predators in the wild. Unlike constrictors, "hots" don't have to expend energy to subdue their prey, and they have less risk of injury from the prey animal.
There is ALWAYS risk when keeping venomous snakes. However, the risk can be managed, and if proper protocols are followed, we can insure our safety. The snake is kept in a custom built enclosure. We built it and "tested" it for a week before bringing the snake home. We checked and double checked for any cracks or spaces that could be used as an escape route, and modified it as needed. We put two locks on the door, and after a few days added two more...you can't be too secure. The locks do more than just make sure the snake stays in...they also make sure that everyone else stays out. We have two boys, 7 and 8, so this step was a total necessity for us. They are both aware of the snake's potential, and know not to touch the enclosure, even though it is secure. Below are our protocols...or RULES of keeping venomous.
Never free handle the snake. Use a hook when it is necessary to move him.
The enclosure will be closed and locked at all times when the boys or guests are present. It is only to be opened when necessary to feed, mist, or clean the enclosure.
When opening the enclosure, two people will be in the room to insure that help can be summoned if necessary.
The hook is kept beside the cage at all times. This way we never have to hunt it down if we need it.
Proper equipment is available to feed the snake, i.e. long tongs and a "hot" feeder, which is a special device for feeding venomous snakes.
Proper first aid supplies are available, i.e. pressure bandage and splints. Of course, these will hopefully never be used. Following protocols will help avoid the need for these, but they are available.
Never open the enclosure unless the snake is visible. Never open the enclosure if he is obviously agitated or seems likely to strike.
NEVER assume that he will not strike. Assume that every time the enclosure is opened he will strike at least once. (he has never struck at anything but food, but assuming he will keeps us aware of his presence and aware of his strike range)
Know the snake's common and scientific names, and have them written down at the enclosure in case of a bite. The doctors will need all the information for proper treatment.
Know the husbandry requirements for the species. This goes for all snakes, venomous or not, but with hots it is essential to keep the snake happy and healthy. Keeping him happy and healthy keeps you from having to handle him as often.
Know the venom type and its effects. Is the snake hemotoxic or neurotoxic or both? What is likely to happen if he bites?
Know how to hook and move the snake before trying it on your own. Work with a hot keeper or breeder before deciding if you can handle it. It is not as easy as they make it look, and it is unsettling at first. Don't go into it unprepared.
Know the behavior of the species. Know their strike range and temperament. Then be prepared for them to do something unexpected.
If you are bit, you will require medical attention. It will not be cheap. You risk loss of fingers, hands, limbs and death if you are tagged by a hot, depending on the species.
If any of the above are too much for you, or if you are nervous about keeping hots, then JUST SAY NO.
Never get a venomous snake to be "cool" or impress your friends. That attitude will get you hurt or dead.