That is a William Hazlitt essay from the Edinburgh Magazine of 1828, reprinted in Table-Talk (scroll to p.165), focusing on why the political uses of nicknames are so problematic. It retains some relevance today:
The only meaning of these vulgar nicknames and party distinctions, where they are urged most violently and confidently, is, that others differ from you in some particular or other (whether it be opinion, dress, clime, or complexion), which you highly disapprove of, forgetting that, by the same rule, they have the very same right to be offended at you because you differ from them. Those who have reason on their side do not make the most obstinate and grievous appeals to prejudice and abusive language.
…a nickname…is a disposable force, that is almost always perverted to mischief. It clothes itself with all the terrors of uncertain abstraction, and there is no end of the abuse to which it is liable but the cunning of those who employ, or the credulity of those who are gulled by it. It is a reserve of the ignorance, bigotry, and intolerance of weak and vulgar minds, brought up where reason fails, and always ready, at a moment’s warning, to be applied to any, the most absurd purposes…a nickname baffles reply.
…the passions are the most ungovernable when they are blindfolded. That malignity is always the most implacable which is accompanied with a sense of weakness, because it is never satisfied with its own success or safety. A nickname carries the weight of the pride, the indolence, the cowardice, the ignorance, and the ill-nature of mankind on its side. It acts by mechanical sympathy on the nerves of society.
…”A nickname is the heaviest stone that the devil can throw at a man.”
There is more excellent analysis at the link, most of all on how the uses of nicknames avoids and runs away from the careful making and unpacking of specific charges. Hazlitt notes the nickname can on the surface sound quite innocent yet nonetheless be a form of powerful invective. For a while the Whigs were called “the Talents,” yet in a manner reeking of implicit scorn.
From Hazlitt, here is another scary part:
I have heard an eminent character boast that he had done more to produce the late war by nicknaming Buonaparte “the Corsican,” than all the state papers and the documents put together.
Here is a brief summary of the essay. Hazlitt remains under-read and underappreciated.
For the pointer to this essay I thank Hollis Robbins.