Finkelstein is famous for writing the the Holocaust industry where he argues a portion of Jewish extreme nationalists shamelessly abuse the Holocaust and antisemitism as a method to smear anyone that disagree with their politics as “antisemitic”. It’s a well supported argument which probably the majority of the world agrees with but doesn’t publicly say it least that aforementioned industry come after them. It’s like some black nationalist woke types that smear over a billion people with white skin as “white supremist” as if everyone with white skin is secretly conspiring against them. Some Islamic extremists play this game with “Islamophobia” too.
On the other hand, Finkelstein made the huge mistake of supporting fanatics Hamas. When Hamas went on their recent murder vacation into Israel it undermined Finkelstein’s credibility even if the main thesis of his book is correct. I can see where the argument self-hating Jew comes from but its really a far leftist thing. An element of the left in most nations is prone to taking extreme positions against their own group to show how they are “against racism”. As the saying goes, two wrongs don’t make a right.