Wearing horns is a traditional symbolic representation of being cuckolded in since European countries, and in some languages the word for cuckold literally translates as ‘horned’ or variations on it. Even the horn sign associated with heavy metal can be very insulting.

If it’s an incel insult, it’s a historically accurate one.

Cool etymology explanation. It’s a pretty well known one, but extra points for being deliberately obtuse.

It’s a sad incel insult because they equate a man’s worth to the ownership of a woman for the purpose of sex, and the loss of it to another man as a loss of their ‘manhood’.

The moment you call someone a cuck or cuckhold, you’re telling the world exactly how reductive and sad your view of the world and the people in it is.