There is HUGE gap between Zionism, and Semitism, as this author has no doubt chosen to ignore.
Modern Zionism is an empirical belief that a Jewish state exist by any means necessary - not my words, but the words of the movement's spokespeople. What this has ended up meaning is that any opposition deserves destruction.
Semitism is just a person's participation in the Jewish faith. Doesn't even need to be part of the organized positions of Judaism.
What this author seems to be saying is that being anti-zionist means you're antisemitic, which is bullshit. There are plenty of Jews around the world who are sick of the Zionist crap, especially Netanyahu.
Being against one faction of a people doesn't mean you're against them al, it simply means you're against the people you say you're against. Has nothing to do with history, faith, or politics. I'm against the current actions of the Israeli government, as are a lot of Jews, and it doesn't make any us antisemitic, just against the Israeli state and Netanyahu.
This article is specifically referring to the Hebrew relation to Judaism, and people being against Jews.
The more general terminology is rarely used to describe all groups much anymore, but a lot of that has to do to the Israeli State kind of exclusively co-opting the use of it.