(CNN)By pledging his allegiance to ISIS during his deadly attack, the Florida gunman tied himself to more than just radical terrorists. Omar Mateen joined ranks with a group that has been relentless and brutal in its persecution of those perceived to deviate from mainstream sexuality.
The gunman, ISIS and a war on sexual minorities
People tortured. Gunned down by firing squads. Beheaded. Burned and stoned to death. According to eyewitnesses and video, this is the fate of many gay people in the lands of ISIS, where they are routinely hunted and murdered because of their sexuality.
At the U.N. Security Council's first-ever briefing on LGBT issues around the world last August, an Iraqi man with a disguised identity testified, "In my society, being gay means death."
He added, when ISIS "kills gays most people are happy because they think we are evil." He went on to describe how ISIS uses phone and Facebook contacts of suspected gays to find others and track them down. "And it is like dominoes," he said, "if one goes the others will be taken down, too."
He was not alone. Subhi Nahas, who fled his home in Syria, told the story of how gay men were hurled from buildings -- their executions captured on video and posted on the Internet. "If a victim did not die," Nahas said, "the townspeople stoned him to death."
ISIS, Al Qaeda and other terror groups justify such violence as part of their faith.
Nihad Awad, national executive director of the Council on American-Islamic Relations, swiftly dismissed that notion in the wake of the Florida killings.
"This is a hate crime. Plain and simple. We condemn it in the strongest possible terms. It violates our principles as Americans and as Muslims. Let me be clear, we have no tolerance for extremism of any kind. We must not tolerate hateful rhetoric that incites violence against minorities."
Still, persecution of gays, lesbians and others who identify as queer is accepted in many parts of the world and not merely by radical groups.
A 2016 report by the International Lesbian, Gay, Bisexual, Trans and Intersex Association cites more than 70 countries in which homosexuality is outlawed, and many of them are clustered around the area where ISIS is strongest.
And in 13 nations (or parts of them) the report notes that homosexual behavior of is punishable by death.
One of the co-authors, Aengus Carroll, notes how the prosecution and punishment of gays is sometimes cloaked in legal proceedings, but is clearly persecution. In Iraq, for example, he says "rogue judges and militias arrest, try, and execute people perceived to express their sexual orientation in ways considered forbidden."
As the United States Ambassador to the U.N., Samantha Power, said following that U.N. briefing: "This is not an issue, by any means, confined to ISIL... You have countries that have criminalize LGBT status."
Whether the Orlando shooter was aware of such systematic brutality is not known.
The specific motivation for this attack and why he targeted this club also remain mysteries. But we know this: according to a U.S. official Mateen's family says he expressed anti-gay feelings, and he told police he himself supported ISIS. And, oftentimes, the two go hand in hand.