During his trial in New South Wales, prosecuting barrister John Agius read from a letter in which Mr Monis described the soldier as a “dirty animal”.
Mr Monis wrote: “Some Jews who blame Hitler for violations of human rights are not much better than him.
“When the body of a murderer of civilians is sent back to Australia, we must not respect the body, such a body does not deserve a respectful ceremony.”
His lawyers dismissed the abuse as a legitimate political exchange, suggesting “insults are a legitimate part of the political discourse”.
The letter to the family of the Jewish solider was one of several that Mr Monis sent to relatives of Australian soldiers who were killed in Afghanistan.
Mr Monis, who received political asylum in Australia in 1996, had been on bail, charged with being an accessory to the murder of his former wife, as well as carrying out more than 40 sexual and indecent assaults.