Batten down the Hatch

Mean "But tear down the Dutch" and in slang was used to express extreme stupidity…

https://vanessariley.com/regcant/A_dictionary_of_slang_jargon_cant-ed%20127.pdf

https://www.dailymail.co.uk/news/article-4824428/NYC-Peter-Stuyvesant-statue-latest-memorial-statue-war.html

https://www.dutchnews.nl/news/2020/06/tearing-down-statues-is-not-the-answer-says-dutch-prime-minister/

https://www.timesofisrael.com/should-new-york-city-remove-statues-of-its-anti-semitic-dutch-governor/