The Bach, commenting on Tur Shulchan Aruch, explains that the decrees of the Yivanim against the Jewish people occurred because the Jew had become “lax in their service.”
Earlier in history, the Beis HaMikdash had been the center of life, the pride of every Jew. Going up to Yerushalayim three times a year was looked upon with excitement and great anticipation, and the effect of the service was appreciated by all. However, by the time of the Chanukah events, that appreciation was long gone. While the kohanim still brought the korbonos, the service in the Beis HaMikdash had lost its luster and glory.
The Bach seems to be saying that all that was to befall the Jewish people was because we no longer approached the Avodah with the appropriate sense of purpose, and therefore it was taken from us. This, however, becomes difficult to understand when we take into perspective what was actually happening in those days
At the time of Chanukah, there was much wrong with the spiritual state of the Jewish people. Ignorance had become profound, and entire generations were no longer brought up in the ways of Torah. The Greek/Syrian philosophy had taken hold, and many Jews considered themselves more Greek than the Greeks. In their homes they spoke the language of Yavan. They schooled their children in the ways of Yavan, and all that they aspired for was acceptance in Greek society.