From reading the NYTimes article [1] it seems clear he’s anti Israel/occupation/bombing and not anti semitic. The pro Israel groups that sought to oppose him getting the job didn’t try to argue that he was anti semitic either, just that he wasn’t ‘civil’ on his Twitter feed.

[1] https://www.nytimes.com/2014/09/13/world/middleeast/professo...

A brief read of the tweets included in the article he links to regarding his firing gives me the impression that it's the latter. In fact there is one tweet of his which references exactly your point about the deliberate confusion of anti-Semitism and legitimate criticism of Israeli policy.

Can't say I've looked into it extensively though.

"You may be too refined to say it, but I'm not: I wish all the fucking West Bank settlers would go missing."

"Zionists: transforming anti-semitism from something horrible into something honorable since 1948."

From: https://en.wikipedia.org/wiki/Steven_Salaita_controversy