The Star of David is not a Jewish holy symbol, having that would be sacrilege anyway, similar to idolatry. It’s not even the Star of David, to be honest.
At some point Jewish secularists in Europe wanted some symbol for the Jewish identity. They picked one very commonly used in the Middle East, by all peoples and religions.
By the way, crescent is not a Muslim holy symbol, too, and with the same implication of idolatry. Though they have in practice accepted it, just like Jews. It’s the symbol of Constantinople, which Ottomans used in line with their pretense to be heirs of Rome (I mean, if Germans can do that, why not them).
Many of the Jews around the world have a very idealized idea of Israel and simply can’t believe it’s bad. See, when you are a member of a demonized (even today) minority, but somewhere is a strong and successful state of your nation that has restored its presence in its cradle 2000 years after being partially wiped out, partially expelled from there, you tend to be irrational.
Also separation of religion and nation is a Western thing, Jewish religion is about a nation, and, by the way, Muslim religion too states that all Muslims are one nation.
EDIT: OK, why the downvotes here? Everything here is factual. And if that’s the paragraph about 2000 years triggering people - that’s a right, yes. The state of Israel sucks, but not the general idea. Same as Sebastia, Malatia, Sis, Sasun, Mush, Van are Armenian till the end of days in my book.