Avram and Sam2:
This is theoretically a fair point, as labels can be broad, but only if you can define what might be halachicly permitted according to our gedolim including Rav Elchonon et al. yet would still fall under the label “Religious Zionism”, never mind secular “Zionism”.
For example, Rav Moshe has a teshuva, as I recall (and I imagine Sam2 knows), that the presence of an Israeli flag in a shul is not A”Z. That this is even a question is certainly illustrative of the topic at hand. Either way, that doesn’t change the reality of the tenets of the religious Zionist faith, which remain assur; but showing the Israeli flag is not A”Z according to Rav Moshe.
Again, the State of Israel and Zionism are shmad, treif, etc. Nothing has changed in this regard. And, if you think objectively about it, it makes no sense (and was roundly forbidden by Rav Elchonon, Rav Chaim Brisker, et al.) to graft secular European Nationalism unto, and in much conflict with, lihavdil, the holy Torah and CH”V fuse the two to make them both into one illegitimate cholent of a religion (and then, on top of that, for some to have the chutzpah to try to pass that off as authentic Judaism).
This is essentially what Rabbi Kook did, as Rabbi Dr. Lichtenstein has more or less admitted in his writings even if he draws a different conclusion, and this is what Rav Elchonon and others called Avoda Zara. That this is forbidden is not a very difficult concept to understand.
So, absent any other definition of “Religious Zionism”, “Religious Zionism” is strictly forbidden.