How is the idiom hit someone below the belt used daily?

This idiom is used frequently when a social "low blow" has occurred, typically in an insult form. This is used in reply to an insult or an action which is insulting to a person on a much deeper level than the usual run-of-the-mill insults. Typically, these insults will be about family, ones mother or a girlfriend/boyfriend. As relating to the moral standard of never striking a man in the groin during the fight, the term "hit below the belt" summarizing the insult as of bad taste.