HaKatan,
I am not saying that R’Elchonon used the words “avoda zara” in a lav davka way. I am saying that R’Elchonon was using avoda zara as a mashul. I highly doubt that R’Elchonon would hold that Israeli flags are assur b’hana, for example, which they would be if Zionism was literaly avoda zara.
Similarly, the Brisker Rav’s statement doesn’t mean that Zionism is an eigel. The Satan is not limited in his tools to literal avoda zara. Rather the Brisker Rav is saying that the Satan was using Zionism as a means to cause Klal Yisroel to stray from the path of Torah.
Zionism isn’t literal avoda zara because it doesn’t require the denial of Hashem or the attribution of divine power to some other being, ChV”Sh, other than Hashem.