It is a lot easier to ban the ownership of a dog than any of the other things you listed. How would you hide the ownership of a pit bull? First, a person would have to find someone selling a pit bull illegally. Sure, criminals could still buy the dogs from other criminals, but the issue here isn't street thugs, it's the random neighbors whose dogs aren't dangerous, until one day they kill someone. Most people won't break the law and seek out criminals to purchase a dog.
And once you have the dog, how do you hide ownership of a dog? Well, you could do so by keeping the dog inside all the time -- but frankly, that would solve the problem, because if the dog is in your house, it can't kill my children. In fact, if it didn't seem cruel to the dog, one could argue that instead of banning the dog, just make it illegal to allow the dogs outside the house.
The problem with the slippery-slope argument is that government already bans ownership of animals it deems dangerous. The precedent is already set. If it was proven that pit bulls were in fact a dangerous breed with no redeeming qualities, a vast majority of people would be happy to let government ban ownership. You wouldn't be breaking down any barriers of existing jurisprudence.
However, the pro-pit-bull argument goes a long way to encouraging people to ban all dogs, or at least most dogs. Because if all dogs can kill kids without reason, and all are equally dangerous, why not allow neighborhoods to ban dogs, to keep their children safe?
I support arguments that discuss whether pit bulls are in fact dangerous or not. I don't think arguing that government has no business banning dangerous animals is a rational argument -- I expect government to take actions to protect my private property rights from acts of others that clearly threaten my life, liberty, and use of my property.
Which again is why I came to this thread, to note that the coconut argument was silly and fallacious.
What domesticated animal has the government banned? Please give me an example.
And before you say ‘lions and tigers’, please consider that although there are federal laws restricting international trafficing, in many places (most, if the WWF is to be believed) there are no restrictions on privately owned tigers.