On this basis, we can understand the wording of the Gemara,1וּבָזֶה יוּבַן לְשׁוֹן הַגְּמָרָא
“When the Greeks entered the Sanctuary, they imparted impurity to all the oil in the Sanctuary.”כְּשֶׁנִּכְנְסוּ יְוָנִים לַהֵיכָל טִמְּאוּ כָּל הַשְּׁמָנִים שֶׁבַּהֵיכָל,
The implication2 of that wording is thatדְּמַשְׁמָעוּת הַלָּשׁוֹן הוּא,
when they entered the Sanctuary, they made a special effort and strove to impart impurity to the oilשֶׁכְּשֶׁנִּכְנְסוּ לַהֵיכָל הִנֵּה הִשְׁתַּדְּלוּ וְנִתְאַמְּצוּ לְטַמֵּא אֶת הַשְּׁמָנִים
(for this was part of their endeavor to, Heaven forbid, vanquish the Jews). As mentioned above, their battle against the Jews was primarily spiritual. Hence, they sought to impart impurity to the oil. To highlight the spiritual forces involved in the conflict:(בִּכְדֵי לְנַצֵּחַ חַס וְשָׁלוֹם אֶת יִשְׂרָאֵל),
The Sanctuary is identified with the Sefirah of Binah of Atzilusכִּי הֵיכָל הוּא בִּינָה,
and oil is identified with the Sefirah of Chochmah of Atzilus, which transcends Binah that is associated with intellect.3וְשֶׁמֶן הוּא חָכְמָה שֶׁלְּמַעְלָה מֵהַשֵּׂכֶל דְּבִינָה
Although Chochmah is translated as “wisdom,” Chochmah is the seminal point from which wisdom derives and ordinary rational thought begins with the potential of Binah. Chochmah, by contrast, represents the bond between intellect and G‑dliness that transcends intellect.
(As mentioned in sec. 2 above, oil is identified with the level of kodesh, holiness in essence, above the holiness associated with any particular entity.)(כַּנִּזְכָּר לְעֵיל סְעִיף ב' שֶׁשֶּׁמֶן הוּא בְּחִינַת קֹדֶשׁ),
Therefore, the Greeks imparted impurity to all the oil in the Sanctuary identified with Binahוְלָכֵן טִמְּאוּ כָּל הַשְּׁמָנִים שֶׁבַּהֵיכָל דְּבִינָה,
in order to achieve their goal of “caus[ing the Jews] to forget Your Torah and transgress the decrees of Your will.” As mentioned above, they did not destroy the oil, they imparted impurity to it. Their intent was to have their worldly approach influence the Jews’ spiritual potentials.בִּכְדֵי לְהָפִיק חַס וְשָׁלוֹם אֶת מְזִמָּתָם "לְהַשְׁכִּיחָם תּוֹרָתֶךָ וּלְהַעֲבִירָם מֵחֻקֵּי רְצוֹנֶךָ",
They desired that the Jews’ study of the Torah and observance of the mitzvos would be motivated solely by the intellect without a bond to G‑d and Holiness.אֶלָּא שֶׁלִּמּוּד הַתּוֹרָה וְקִיּוּם הַמִּצְווֹת יִהְיוּ רַק מִצַּד הַשֵּׂכֶל.

Summary

On this basis of the above concepts, we can understand why the Greeks imparted impurity to all the oil in the Sanctuary. Since their conflict with the Jews was spiritual they sought to “cause [the Jews] to forget Your Torah and transgress the decrees of Your will,” seeking to impair the Jews’ spiritual potential. Oil is identified with Chochmah, the potential that makes possible the bond between intellect and G‑dliness that transcends intellect.