ok I actually wanted to look up what antisematism actually means since the only context I've seen it is israel, so I looked up what sematism is which lead me to one who has sematic qualities which is:
Semitic
of, relating to, or constituting a subfamily of the Afro-Asiatic language family that includes Hebrew, Aramaic, Arabic, and Amharic
Saudi Arabia is arabic so technically they're correct?
"semitic" has this broader meaning, yes, but the specific term "antisemitism" is only used to refer to Jews, not to Arabs (or, for that matter, Amharic-speaking Ethiopians).
It also doesn't specifically refer to the State of Israel, but to Jews everywhere.
As a sibling commenter noted, Islamophobia is probably the common word used in US media for this concept. Islamism, by contrast, is typically used in the English-speaking world to refer specifically to the ideological movements that hold that Islam should be the basis of political systems (that is, establishing explicitly Islamic states; implementing Sharia as the basis of state legal systems; etc). So anti-Islamism, then, would carry a different meaning than Islamophobia or anti-Islamic or anti-Arab sentiment more generally.
"Islamophobia" is in fact a widely-used English word. (But it doesn't quite mean the same thing as "prejudice against Arabs", since "Muslims" and "Arabs" are different sets).
Similar to other racial categories these do not have a real link to reality, and are mostly artifacts of how racist tried to link these to something tangible (Think how White is applied to a specific subset of people with pale skin)
