Democrats do not understand what motivates the jihadis
...To believe that they are motivated by disappointment in not being able to come to America is to believe they are so mentally unstable, to begin with, that any disappointment turns them into a mass murderer. To believe that you have to have a low regard for the ability of Muslims to reason.
Meleagrou-Hitchens's program released an invaluable report last year that studied motivations of Americans who had declared allegiance to the Islamic State. It found that the motivations ranged from sympathy for the plight of Syrians suffering under their dictator's war to a sense of religious obligation to join a new utopian Islamic caliphate.
Another problem with this argument is that it fails to account for the significant rise in radical Islamic terror under President Barack Obama. He went out of his way to counter the jihadist worldview. He began his presidency by delivering a speech to the Islamic world from Cairo, in which he stressed his own administration's respect for Islam. He promised, and ultimately failed to, close Guantanamo; he withdrew U.S. troops from Iraq in 2011, and he scrubbed terms like "radical Islam" and "war on terror" from the government's lexicon.
And yet despite his efforts, the FBI arrested more Americans for joining Islamic terrorist groups during his presidency than during that of George W. Bush. And while Obama decimated al Qaeda's central leadership following the raid that killed Osama bin Laden, al Qaeda's franchises in Yemen, Somalia and Libya grew stronger. Meanwhile, the Islamic State broke away from al Qaeda during Obama's presidency and managed to gain territory in Syria and Iraq. Only now has the military campaign to liberate Mosul shown some success.
It's true that Obama also did many things jihadists did not like during his presidency. For example, he used drone strikes against more of them than his predecessor did. And when the U.S. Supreme Court recognized the legal right to gay marriage, Twitter accounts affiliated with the Islamic State posted video of gay men being thrown to their deaths off of high buildings in Raqqa, with the hashtag #lovewins. The Islamic State didn't like the Iran nuclear deal, either. After all, Shiites like the Iran regime are seen as apostates, and in the battle for Syria, the Iranians are on the side of the oppressors.
This gets to the most important point. The fanatics who seek to recreate an eighth-century caliphate have an endless supply of grievances about our open society. If we succumb to the fallacy that we can counter their propaganda by not doing things they could exploit for propaganda purposes, we are giving them too much power.