William Floyd (1871 - 1943) Editor of The Arbitrator, a New York atheist magazine and signer of A Humanist Manifesto I (1933) wrote The Mistakes of Jesus in 1932.
Sadly, an extensive search for Floyd's credentials was fruitless so I am incapable of commenting on his authority to make such statements as expressed in this secular sermon. Though Floyd does raise a few questions of merit, in all he personally shows ignorance of the world, customs, and mores of the Ancient Near East which explains much of Jesus' actions through the perspective of the culture and time in which he lived. Also, new archaeological discoveries that Floyd would not have been privy to, have shown some of his assertions about Jesus' "errors" to be incorrect, such as the discovery of manuscript fragments that move the authorship of the Gospels from the fifth century solidly into the first.
Nonetheless, The Mistakes of Jesus is an interesting work from the declining years of the Golden Age of Atheism before World War II and the bloody regimes of Hitler and Stalin put an end to the idealism of secular humanism once and for all. Atheists and skeptics of all stripes will find the work to be comforting bed time reading while Christian apologists will find hardly a question worth considering once they have wandered through all the arguments by outrage and blind appeal to authority without identifying said authority.