Millennia of migrations, inter-marriage and conversions make contemporary Jews related to ancient Hebrews as much as todays Roman Catholics are to ancient Romans.

Even if they were, this would still not justify Zionism: my "ancestral homeland" 3000 years ago may well be Israel, Peru or Timbuctu, but that does not give me the right to displace or dominate those who lived there for centuries and have no other home.