Why do you pronounce guilt on the Jewish people? You should try to find a limud zechus as in Makos 7a.
A Rav
once told me that the Gemara says that in order to be a Judge on the
Sanhedrin one first had to prove that a sheretz does not cause tuma. But
doesn't a sheretz always cause tuma? Yes, but the point is that before
paskening a halachah of guilt on someone, especially masses of Jews, one
has to really try to very hard to look at every conceiveable angle to
exonerate, even attempting to use arguments and analysis that may later
prove flawd. Not to pervert justice, but within the framework of halachah.
And as R. Tarfon and R. Akiva say in Makos, 7a, "If we were on the
Sanhedrin, no one would ever receive the death penalty, (i.e. they could
have always been able to figure out an halachic way to exonerate the
accused)" (Yes, I'm aware that R. Shimon ben Gamliel responded that had
they been on the Sanhedrin, they would have increased the number of
murderers in Israel).
I don't see this so much as a question of pronouncing guilt on Jews for something they did in the past. The past is Hashem's business. We have to decide what is permitted or not permitted for the future. And to permit something that carries such a severe penalty and has to do with the foundations of the world, exile and redemption, we would have to look from every conceivable angle and be absolutely sure we are correct.
Furthermore, I think the sin of the Three Oaths is more in the present and future than in the past. In the early years of the Zionist movement and the state, it was largely a secular movement with a minority of religious tag-alongs. What a secular Jewish movement does, it could be argued, does not really represent Klal Yisroel. The existence of Jewish Communist groups in Russia and Poland did not mean that Communism was a Jewish enterprise. But now the tables have been turned and it is the religious, including many chareidim, who are more Zionist than the secular, speaking in the name of the Torah and refusing to give back a millimeter of land. Furthermore, the religious communities are growing demographically and will soon outnumber the secular. Therefore, when we discuss the question of the Three Oaths we are not discussing the past but rather present and future: what does the Torah really say? What should we do now? Our purpose is not to point fingers and blast other Jews, but to give guidance as to where the Jewish people should go from here.