“There are foolish people who recognize their foolishness and use it skillfully.”

"1901", p. 76. Sometimes misquoted as "If fifty million people say a foolish thing, it is still a foolish thing". Sometimes misattributed to Bertrand Russell or Anatole France
A Writer's Notebook (1946)

W. Somerset Maugham, A Writer's Notebook (1949), entry for 1901
Sometimes misquoted as "If fifty million people say a foolish thing, it is still a foolish thing."
Sometimes misattributed to Anatole France
Note that Russell does say something similar in Marriage and Morals (1929): "The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd; indeed in view of the silliness of the majority of mankind, a widespread belief is more likely to be foolish than sensible."
Misattributed

Fors Clavigera, letter xxxvii, (1 January 1874).
Fors Clavigera (1871-1878 and 1880-1884)

Google's Eric Schmidt calls for 'spell-checkers for hate and harassment' https://www.theguardian.com/technology/2015/dec/08/googles-eric-schmidt-spell-checkers-hate-harassment-terrorism, 8 December 2015, by Alex Hern.
2010s, 2015
Context: We are losing a lot of people to the Internet. We have to do something. We have to go see Bill Gates and a lot of different people that really understand what’s happening. We have to talk to them [about], maybe in certain areas, closing that Internet up in some way. Some people will say, ‘Freedom of speech, Freedom of speech’. These are foolish people.

Source: The Book of Tea

Prologue (p. 8)
Nifft the Lean (1982)

Travis McGee series, Nightmare in Pink (1964)
Context: It isn't foolish or wicked to enjoy. Wickedness is hurting people on purpose. I love what you are and who you are and how you are. You give me great joy. And you make horrible coffee.