Just came back from my Google on Greenberg Israel. You beat me to it.
Greenberg has, in fact, actively interjected himself as an American progressive into the politics of Israel as an anti-Bibi pied piper.
I can’t believe Israel doesn’t just send him to Libya, Afghanistan or Iraq when he tries to enter the country.
I'm sure there are some in Israel who might like to see that, but remember that Greenberg is Jewish and Israel was created as a Jewish state. It wouldn't be too good a public relations move, nor would it be consistent with Israeli law.
Better that Israel enacts some legislation prohibiting foreigners from playing too much of a role in their election process, if they don't already have some such law.