A dark shadow passed over Paris, the City of Light, on Jan. 7 .  Well-organized, well-trained killers murdered 13 people in the name of Allah. As Shakespeare said 500 years earlier, about the heinous murder of King Duncan by Macbeth, “O horror, horror, horror! Tongue nor heart cannot conceive nor name thee.”

Indeed, recent horrors in the name of Allah have been so gruesome it is impossible to conceive the mutilated reason, the perverted concept of God’s will, and the unvarnished rage that has subverted the once admired religion.

The killers are ruthless and depraved, but those who inspire them are evil and those who tolerate them are guilty.

In 2005, when a Danish newspaper published 12 cartoons depicting the Prophet Mohammed and riots were stirred up against the publishers, a meeting was arranged at a community room in the basement of The Washington Times. It was not organized by the newspaper but, as I recall, by an interfaith group. There were several fringe “let’s be nice” speakers before the main event.

The main event was the Danish ambassador and, to a lesser extent, myself. The ambassador spoke about life in Denmark and what the Danish government would do to understand and listen to the concerns of the Muslim community. My role was to defend and explain the Western concept of freedom of speech and the place satire. The overflow audience, which by dress and appearance was dominated by emigrants from Pakistan, was implacable.

I have spoken to some hostile audiences in my time, but this one was special: no compromise, no quarter. Nor interest in cultures other than their own. Ugly and insatiable rage came out in their questions.

They did not want to know about the values of the country that had given their brethren sanctuary, education, healthcare and a decent life. My audience only wanted to know why the blasphemers in Denmark and Norway (the cartoons were reprinted there) were not being punished. For good measure, they wanted to know why the American media was so committed to heresy against Islam. No thought that they had moved voluntarily to the United States and were enjoying three of its great freedoms: freedom to assemble, freedom of speech and freedom of religion.

They wanted absolute subjection of all Western values to the dictates of Islam. They had been fired up and they were angry, self-righteous and obdurate.

In 2009, I was invited to a conference of world religions in Astana, Kazakhstan. There were maybe 100 religions present, but at a featured session the conference degenerated into an Islamic diatribe against sexuality and the treatment of women (mostly in advertising) in the West. No dialogue. No discussion. Absolute certainty.

I mention this because of the reaction to the barbarity in Paris, and to a string of other barbarous murders across the world, from Muslims has been so muted.

“Je Suis Charlie” said millions of people in dozens of countries in sympathy with the murdered journalists and with their fight for press freedom. From Muslim leaders in the West, including the Council on American-Islamic Relations in the United States, there were statements of condemnation but no sense of outrage. From the bulk of the followers of Islam there was nothing. There never is. Not when innocent children are shot in their schools, or when aid workers are beheaded, or when or when satirical journalists are executed. The Muslim multitudes have acquiesced to evil.

When will those who believe deeply in Islam take to the streets to denounce the excesses of the few? After the horror in Paris, British Muslims took to the BBC to mildly criticize the murders, but more to vigorously demand a better deal for Muslims in Britain.

The medieval certainty of the leadership of Islam is endorsed by the silence of its congregants. The silence of the millions gives a kind of absolution to the extremists, intoxicated with fervor and hate. It will all go on until the good Muslims stand up and are heard. The guilt of silence hangs over Islam.

Llewellyn King is executive producer and host of “White House Chronicle” on PBS. His e-mail is lking@kingpublishing.com.