Legitimately, the fact that they're an American org will usually be a fair indicator.

The zionist movement fell flat on its face in the US during the foundation of Israel, so most pro-palestinian jewish activism will be based out of the US as well.

This dynamic has intensified enough since that initial split that Israeli Judaism has actually taken on fundamentally different qualities from American Judaism, to the point where some scholars would consider them separate denominational groups.

It's also fostered enough bad blood that a frequent dismissal of Israelis when hearing of Jews who oppose the settlement project is to say "they must just be stupid Americans."

They legit try to do the "they aren't authentic!" bit other old worlders and Latine folks will whip out when putting down their American cousins for not being identical to them, except with the Israelis it's even funnier because bitch you ain't where you came from either, that was literally the whole point of this great displacement project y'all whipped up!