Dutch uncle is an informal term for a person who issues frank, harsh or severe comments and criticism to educate, encourage or admonish someone.
Thus, a "Dutch uncle" is the reverse of what is normally thought of as avuncular or uncle-like (indulgent and permissive).
During the Anglo-Dutch Wars between England and the Netherlands in the 17th century, the English language gained an array of insults (including "Dutch uncle"), such as: These terms also gained prominence in 17th-century New England during its rivalry with New Netherland, which the Dutch captured (and later recaptured) during the Second Anglo-Dutch War.
Netherlands: A Survival Guide to Customs and Etiquette as "practical, direct, outspoken, stubborn, well-organised, blunt and thinking they are always right."
"[1] Another book that advocates this theory is The UnDutchables, which assigns comparable characteristics to Dutch people: "not lacking in self-esteem ... caught up in a cycle of endless envy ... always speak their mind ... frank, obstinate, blunt", basically summed up by the phrase "the natives thrive on shaking their fingers at and scolding each other.