What is wrong with us people is that we are fed up to breaking point with being denied a basic human right - quiet in our own homes. We want to get to sleep at a reasonable time, not lie in bed until 4am waiting for someone's stupid pet to condescend to be quiet for a couple of hours (if we're lucky). We want to be able to enjoy our time at home without constant jarring, unpleasant and stressful sound intrusion from the dog next door. We simply want to get out lives back.
If the law in most countries was as ready to deal with this invasion of privacy as it is to deal with minor motoring offences and people having a crafty ciggie in an empty public building, nobody would think about harming the dogs in question. But it isn't so we do.
Imagine this scenario: some equipment is left on a building site in a residential area - equipment which lets out a series of random, loud noises at all times of day and night. Complaints to the authorities get nowhere. How long would it be before someone found a way to disable the equipment? Not long, I'd say. That would be vandalism and therefore a crime, but who could blame the residents for doing it?
It is just the same with a dog. If a dog is all that stands between someone exchanging a miserable life for a normal one, the dog has to go. Ideally this would be a matter of the dog being kept inside or, in the last resort, removed by the authorities. But this does not happen, so sooner or later someone is going to do the only thing they can - eliminate the dog themselves. It's illegal and immoral but it's the only thing they can do, just as stealing a bite to eat from a shop may be the only action available to someone who has no money and is starving. Neither action is right but both are understandable.
I agree with you on one point - some of the suggestions on here are somewhat extreme and in some cases impractical, such as the one you mention. That said, if someone's been driven to the point of madness for months or even years by a dog robbing them of their basic human rights, it's hardly surprising that they will come to hate that dog, and won't care how much it suffers as long as they can get their peace and quiet back. We don't think that way when the source of the noise is human, e.g. a screaming child, however annoying the noise is simply BECAUSE we are dealing with a human being. A dog is NOT human, so when it pushes us to the limit we come to see it as nothing more than a noisy machine, even if we generally like dogs, but with one difference - the dog chooses to bark, the machine has no choice whether it makes a noise or not. So we will eventually feel such rage and hatred towards it that we use whatever method we can - however cruel - to shut it down. If that's sick, so be it - the sickness could have been prevented by the owner training the dog properly in the first place. Instead of which, the stupid, lazy owner's selfishness has created a number of victims: him/herself, when some "gets at" the dog; the unfortunate neighbour who has had to put up with the noise, and of course the poor dog itself.