I don't understand why they would be 'stunned' - this anti-semetism filtered through to the blacks in the US who converted to islam, after the example of Malcolm X, who converted to sunni islam in 1964 and met with the Mufti whom he described in glowing terms...
Realize that history is hardly taught at all in American schools. History that is taught has been massaged with an eye to PC. The Nazi-Muslim connection has been scrubbed by the Left. While there is a connection through the Black Muslims, the average American knows very little about what they believe. The average American has been dumbed down with “diversity” nonsense. When you tell them the truth, you usually get, “Really? I didn’t know that.” And then these same Americans flush the knowledge down the memory hole.