It took only a few days. And it is indicative of the sort of support Trump has garnered: Racists, conspiracy theorists, white supremacists, and the rest of the far-right fringe were quick to declare Democratic convention speaker Khizr Khan and his wife are not truly patriotic Muslims—and much, much worse.
Roger Stone, a longtime Trump ally and adviser, is promoting smears against fallen U.S. Army Captain Humayun Khan and his family. Stone is claiming that Khizr Khan, Capt. Kahn’s father, is a “Muslim Brotherhood agent” and is promoting an article suggesting Humayun Khan was a double agent working for Al-Qaeda. [...]He tweeted on July 31 that Khan is “more than an aggrieved father of a Muslim son- he's Muslim Brotherhood agent helping Hillary” and Khizr Khan is "traced to the same radical Muslim group as @HumaAbedin.”
Republican operative Roger Stone can best be described as the illegitimate love child of Karl Rove and a dirty bin of used heroin needles, so it's not surprising that he personally was quick to promote the notion that the patriotic Muslim American family seen onstage were probably terrorist agents liked to Muslim Brotherhood and whose dead U.S. Army son was, according to the truly rancid conspiracy-riddled article he linked to, probably a double agent "working for the US and Al-Qaeda" who was "killed before his Islamist mission was accomplished."
Stone is an avid and prolific liar—who just happens to have been a "friend" of Donald Trump for, according to him, decades. The post he is referring to is by the venomous conspiracy theorist Walid Shoebat, and is par for the far-right course. (Indeed, the anti-Muslim far right has long supposed that a host of prominent Muslims or Muslim-linked Americans are "agents" of the terrorists, from Hillary Clinton's aide Huma Abedin to conservative anti-tax kingpin Grover Norquist. The claims are always vitriolic, and the proof is always ephemeral or simply fabricated.)
It is not possible, according to this theory, that there is such a thing as a patriotic Muslim American. They are all up to something; they are all working towards Sharia or are secretly in league with terrorists, and their dead Army sons were probably terrorists after all—even while they were serving their country, and dying for it. The similarity to pre-war Nazi rhetoric is too obvious to ignore. Under this theory, it is impossible for the ethnic other to love their nation. They are all colluding behind the scenes. They are seeking to destabilize us, they have secret connections to each other that they will use to bring us down, their mere presence is dangerous to us, and if we do not act to bar or banish them, they will destroy us.
But it wasn't just human urinal cake Roger Stone. The new claim spread like wildfire, both from advocates inside and outside Trump's campaign.