( CNN ) -- When a man with hands drenched in blood stands just feet away from the body of a person he just hacked to death , still holding the murder weapons , we want to believe he must be crazy . How else can our minds grasp the evidence that someone would carry out an act of such inconceivable brutality ? We do n't yet know all the details surrounding Wednesday 's killing in London . But the fact is we have seen this type of attack before , and even before one of the suspects started ranting to passers-by , we had a pretty good idea what to expect . This killing of a young British soldier was not an act of insanity . It was part of a pattern that has struck in many parts of the world before . This was the product of extreme Islamist radicalism we have all come to recognize . Some will rush to blame Muslims or Islam for what happened , but it 's important to be clear and not to mince words . Islam is not the enemy . Muslims are not the enemy . Terrorism is not the enemy . The enemy is the radical Islamist ideology that justifies any atrocity committed for political motives . The enemies are the people who promote this dogma and encourage others to engage in actions that offend and assault our humanity -- and theirs . As information started trickling in from London , the familiar phrases started emerging , confirming our initial suspicions and no doubt disheartening Muslims who would like to see their religion stop having any association with these atrocities . Witnesses said they heard the two men shouting `` Allahu Akbar '' as they worked to dismember their victim . They say one of them breathlessly declared `` By almighty Allah we will never stop fighting you until you leave us alone . '' A similar attack happened a few years ago in Amsterdam . The Dutch filmmaker and columnist Theo van Gogh was assassinated and nearly decapitated by a Muslim radical angered by van Gogh 's work criticizing Islam . The London murderers apparently justified their butchery as resentment over Western troops fighting in Muslim lands . `` Muslims are dying daily , '' the man with the bloody hands said . But before accepting that argument at face value , consider that radical Islamists have found other reasons to slaughter those who offend them . And the threshold for triggering brutality seems rather movable . The Islamist radical who murdered van Gogh , Mohammed Bouyeri , used a knife to pin a letter to his victim 's body , explaining his actions and threatening to kill Ayaan Hirsi Ali , an ex-Muslim and friend of the director , who remains a fierce critic of Islam . The letter is a screed against Jews and an attempt to intimidate anyone who speaks critically of Islam . Islamist radicalism provided the twisted justification for the Boston Marathon bombings , for the videotaped decapitation of journalist Daniel Pearl , for the shooting rampage of Maj. Nidal Hassan , who killed 13 people in Fort Hood , Texas . And let 's not forget 9/11 , the crown jewel of murderous achievements . Their political/religious ideology has motivated killers in Madrid , London , Jerusalem , Tel Aviv , as well as Syria , Nigeria , Indonesia and Iraq . The creed that demands murder , sometimes murder-suicide , for perceived offenses against Islam and against Muslims constitutes a threat to societies at large , not just to Westerners and non-Muslims . In fact , a study finds that Muslims are its most numerous victims . While police were still working the crime scene in London , British Prime Minister David Cameron said the attack was probably an act of terrorism . The question of whether this particular incident falls under the label of terrorism is not particularly useful . We will hear discussions about whether the perpetrators belonged to a larger organization or were , instead , `` lone wolves '' or `` self-radicalized . '' In the end , the purpose was political intimidation , and inciting fear was its political objective . For what it 's worth , that 's terrorism . But that does not identify the enemy that must be fought . The killing in broad daylight in London 's Woolwich neighborhood belongs in the category of Islamist radical attacks , the same that brought 9/11 , the Boko Haram massacres in Nigeria , restaurant bombings in Tel Aviv , night club killings in Bali , street explosions in Baghdad , hotel bombings in Amman and many other massacres in many countries . Each incident has its own peculiarities , its own list of grievances . But they all contain the same explosive ideology . Most Muslims strongly oppose this kind of brutality . But a recent Pew poll showed significant minorities favor actions such as suicide bombings `` in defense of Islam . '' A troubling 29 % of Egyptian Muslims say suicide bombings can be justified , so do 40 % of Muslims in the Palestinian Territories , 15 % in Jordan and 18 % in Malaysia . The `` defense of Islam '' means different things to different people . Extremists have killed to defend Islam from modern westernized culture . They have killed women for daring to go to school . The victims often have nothing to do with the alleged offense . The Tsarnaev brothers ' victims in Boston had nothing to do with the offenses that angered their killers . An important element in the fight against this pernicious , callous enemy is a campaign to undermine the ideology 's appeal within Muslim communities everywhere . There is much work to do , particularly by the vast majority of Muslims who reject extremism , by their leaders who must be pressured by all of us to make the ironclad case that nothing , nothing in the world , justifies the kind of viciousness that assaulted our senses in London and has done so in too many places for too many years . The opinions expressed in this commentary are solely those of Frida Ghitis .
Frida Ghitis : We want to believe hacking suspects are crazy to explain the atrocity . Ghitis : But it appears , as it has so often , radical Islamist ideology fueled attack . Islam , Muslims or terrorism are not the enemy , she says . It is this murderous ideology . The mission of the Media Research Center is to create a media culture in America where truth and liberty flourish. We need campaigns in Muslim communities everywhere against its appeal .