They are indeed savages guided by an immoral prophet and 'holy' writings that encourage behavior toward 'infidels' such as hostage-taking, rape, kidnapping for ransom, and looting, but maybe 'stupid' is too strong a word to use here.
Clearly they have taken the measure of the man in the White House, concluded that he is a fool and a weak and incompetent leader, and are acting accordingly.
Gosh. I wonder if he’s a Muslim! ; )