The Reason Behind Judt's Zionism?

Even though it may sound completely ignorant, I was not sure what Zionism was before reading this book. Judt never explains what the belief is and I was therefore reading about a man who was interested in Zionism without even knowing what it was. 

This is why I decided to investigate and found out that Zionism is a form of nationalism of jews that supports a nation state, referred to as Land of Israel, for all jews to return to. Throughout the book, Judt sustains that he is not very religious, but at the same time he has a strong interest for Zionism. Judt criticizes jews that are highly religious, which makes me wonder how he would ever be able to live with them under one nation state? Of course, there is nothing wrong with these jews in my opinion, but if this man couldn't tolerate them then how would living with them be any easier? 

Besides, this form of nationalism requires a strong pride in religion, which at one point in the book, Judt says is harmful and unhealthy to a human being. Of course, any obsession or excess of something can't be beneficial. 

Another thing that stood out to me with this interest is that Judt was never religious at all and did not comply with many requirements of the jewish faith. In fact, he didn't support many of the main beliefs of the religion. Then again, Judt could have had different periods that he didn't discuss in the memoir in which he felt differently towards his religion.

Does Judt discuss more in depth his Zionist beliefs in any of his other books? Has he participated in any  been involved in any movements that represent this form of the religion?