The simple answer must be that the three oaths do not apply when the nations try to prevent the Jewish people from observing the Torah. The Chashmona'im fought to liberate the Beis ha'Mikdash which the Greeks had defiled. The three oaths would not apply to this defensive action.

I found that the Klausenberger Rebbe zt'l writes on the lines of my above answer, but with a lot more explanation, of course.

1) This is to be found in Sefer Shefa Chayim on Parshas Vayeshev. It is in Ma'amar 3, section 3.

The Shefa Chayim explains that when Yosef ha'Tzadik was young he believed that one should be "Dochek ha'Ketz." This is actually one of the six Shevu'os mentioned in our Gemara, according to the reading of Rashi (DH v'she'Lo), that we promised not to do. Rashi explains that this is derived from the word "Dochek" and means one should not push too hard. One should not make too many petitions to Hash-m that the Mashi'ach should come.

2) This was the argument between Yosef and his brothers. Yosef believed that there was so much darkness in the world, that the time had arrived that there was no choice but to be "Dochek Es ha'Ketz." Yosef's brothers disagreed and believed that as long as their father Yaakov was alive the darkness in the world was not great enough to justify being Dochek Es ha'Ketz. Because Yosef believed that the world was full of spiritual "snakes and scorpions" his punishment was to be thrown into a pit which was full of physical snakes and scorpions.

3) We now transfer ourselves from the situation of Yosef in the pit to the situation thousands of years later when the entire Jewish people was in the "pit" of Greek domination. A terrible spiritual darkness covered the world, as the Midrash (Bereshis Rabah 2:4) tells us that "the darkness over the waters" (Bereshis 1:2) refers to the Greek exile when only a few people remained faithful to Hash-m and His Torah. The situation was so bad that it seemed that it was impossible to overcome the Tum'ah in the world and people seemed to no longer possess free choice. It was on this background that Matisyahu gathered courage to fight the Greeks and gain a supernatural victory over the world's superpower of the time.

4) The Shefa Chayim then cites a Midrash Peli'ah #31 which explains the verse (Shir ha'Shirim 4:17), "The mandrakes give off a fragance, and at our doors is every delicacy." The Midrash says that "the mandrakes give off their fragrance" refers to Reuven who saved Yosef from the pit (Reuven is referred to as a mandrake because that is the fruit that he brought to his mother from the field). "At our doors is every delicacy" refers to the Chanukah candles we light at our doors. The connection between Yosef and Chanukah is that it is only in such dire circumstances that one is permitted to be "Dochek Es ha'Ketz." Matisyahu was Dochek Es ha'Ketz because there was absolutely no other alternative for Klal Yisrael. Similarly, a miracle happened to save Yosef from the snakes and scorpions because there was no other way out.

5) The Shefa Chayim is discussing explicitly being Dochek Es ha'Ketz, not rebelling against the nations, but it seems to me that in this respect there would be no difference between these two oaths. What we learn from Matisyahu is that one may only rebel against the nations in a very extreme crisis, similar to that which existed in the time of the Chashmona'im.

Kol Tuv,

Dovid Bloom