Fighting Zionism is like fighting chalav stam
I tend to view being zealous over
the issue of the oaths along the lines of one who might be zealous for
chalav yisroel vs. chalav stam. I wouldn't doubt that there are some who
can bring arguments to prove that chalav yisroel must be the only dairy we
can eat; and such a person could also probably claim that those who eat
chalav stam are damaging their souls to eternal damnation, and that those
who sell chalav stam are in the category of sinning against world Jewry and
misleading them, and that such a person may also be able to prove that
every leading Rabbi of the past ruled that chalav stam is forbidden and only
certain modern Rabbi's have become more makil for no good reasons, etc.
Perhaps such a person will create a website called "True Torah Jews Against
Chalav Stam." Not that it's not better to choose to eat chalav yisroel
only, and not that one should not raise the issues in favor of it, but to
be zealousy anti-chalav stam and anti those who are willing to hold by the
lenieniency, no matter how "silly" one might think that leniency is, is
going too far in my opinion, all things considered. So here too. We have
those who say that the oaths are interdependant, and others who say that the
nations voted in favor of a Jewish government, and others who claim that the
oaths are not halachic, and others who say that afte the fact we should
accept or even support such a governments existance. To some these all may
seem like clear cut refutable arguements. Similar to those who say that
relying on U.S. RDA to fine gentile farmers is satisfactory enough to trust
that gentile farmers won't sell non-kosher milk as kosher is also clearly
refutable due to a gentile farmer's willingness to forego a small fine with
the chance of making bigger profits. There are those like R. Schneerson who
held that due to the fact that there are millions of Jews now living in
Israel, the sakana of forcing out a Jewish government and its army to be
replaced by Arab pera adamim overrides the oaths, and that the solution is
not to expel all the Jews from the Land. Is one to say that due to holding
such a view that R. Schneerson was therefore a "Zionist" and as such was
also a "kofer" since such a position fails to advocate promoting a zealous
stance of returning to a time when the oaths were being observed? And from
other angles such as the issue of the national desecration of God's name
versus the continuation of the oaths, one could take a less zealous stance
vis a vis being pro-oath-golus.
Your comparison to chalav yisroel is not good because Reb Moshe and others who permit government supervised milk are still upholding Chazal's prohibition of chalav akum in the situation Chazal were referring to - private gentile farmers, which was the situation throughout the ages. They are only saying that milk sold in stores today does not fit into the category of what Chazal forbade. But here in the case of the oaths, it is abundantly clear to us today, in light of the events of our century, that King Solomon and Chazal meant the oaths specifically to refer to Zionism. With their ruach hakodesh they foresaw the Zionist movement. This is explicit in the Rambam's Iggeres Teiman: "Because Solomon knew with ruach hakodesh that this nation, during its long exile, would push to move before its proper time, and they would perish because of this and troubles would befall them, and so he warned against doing this&" Every other false messianic movement in Jewish history is peanuts compared to Zionism. Finding a loophole to say that Zionism does not violate the oaths is like finding a loophole according to which all milk that has ever been sold by gentile farmers everywhere is not forbidden as chalav akum.
More importantly, Zionism is not just an issue of halacha; it is an issue of emunah. If one holds that milk produced today by companies is forbidden, those who eat it are transgressing a single rabbinic prohibition, but they still deserve to be called Jews, Orthodox Jews, because they believe in the 13 Principles of Faith. One who distorts one of those principles is in a totally different category. If a large percentage of the Jewish people worshipped an idol, even if they had poskim who wrote long books about how exactly it was permitted according to halacha, we who oppose them would definitely be justified in launching a zealous movement against them, arguing that they have no right to call themselves Jews and so on.
Zionism too has distorted the principle of "im kol zeh achakeh lo" - waiting for moshiach. Part of that is believing that Hashem sent us to exile and only He can send moshiach and redeem us. It is almost not the same religion anymore.