The Magen David is not a Jewish symbol; it is a symbol of the Davidian monarchy, which just so happens to be Jewish. Jews don’t worship physical shapes, such as the Cursedian “x” or Mohammedan crescent.
The shape itself consists of one “Dalet” (the letter) superimposed on another, from the name “David” (with or without a joining “Vav” in the middle). In Ksav Ivri, that is, where the Dalet looks like the Greek Delta or triangle.
That Jews had this symbol in synagogues demonstrates once more the truth of what I said here:
By the way, this is another thing anti-Zionists get wrong. Even if/when Jews are not a national entity, avoiding confrontation, too, has limits, and each situation must be judged anew. They never judge anything religious anew, sadly.