How can law ruin the lives of men?

In part 4, chapter 5 of Gulliver's Travels, Gulliver is in the land of the Houyhnhnms, a race of ultra-rational, intelligent horse-like creatures. As happens at every stop on his journey, Gulliver relates some of the strange customs of his home country. The subject of conversation between Gulliver and the master horse soon turns to law. The Houyhnhnms have their laws—only they don't refer to them as such—but they are devised on a purely rational, utilitarian basis, that is for the greatest good of the greatest number of citizens. So when Gulliver mentions that the law in England can be the ruin of any man, the response of the master horse is one of utter incredulity.
The main problem with English law, according to Gulliver, is the legal profession. Lawyers are little more than professional sophists who will gladly say that white is black and vice versa if they are paid enough money to do so. They do not concern themselves with justice, only with making sure that the law works effectively for their clients, irrespective of the financial and reputational ruin that this may bring to other men.
According to Gulliver's explanation, the law is cloaked in a monstrous, impenetrable jargon that no one can understand. Lawyers skillfully exploit this widespread ignorance of the law to line their pockets at the expense of justice. What matters is not whether a particular case is right or wrong, but whether a lawyer is adept at spinning an appropriately convincing, complex web of sophistry in front of a judge. Only the very best lawyers are capable of doing so consistently, and they cost money. Hence the law becomes an instrument that serves the narrow interests of the rich and powerful. Justice doesn't enter into the equation at all.