Literally they are correct. Arabs are also Semites.
Semite: a : a member of any of a number of peoples of ancient southwestern Asia including the Akkadians, Phoenicians, Hebrews, and Arabs
They are anti-Hebrew but not anti-Semite.
The terms “anti-Semitic” and “anti-semitism” were expressly coined to refer to prejudice and hatred of Jews by a German professor named Wilhelm Marr in 1879; he founded a group called “The Anti-Semitic League” that year.