I guess this is kinda two separate questions in one: why did the Christians include it in theirs, and why did the Jews not? Not knowing much about Christian theology, I’m confused as to why they thought it ought to be part of their religious texts, whereas I would think the Jews would include the narrative of them fighting against those who tried to take away their religion.
How much do we know in general about the selection of books for the Tanakh?
/u/Flubb answers this question here.
I think I found one reason why.
Aristobulus I (great-grandson of Mattathias of the Maccabees) became both High Priest of Israel and King of Israel. The Pharisees did not like that. They thought that only descendants of King David could become King in Israel. The Maccabees and Aristobulus I are from the Levite priestly division of Jehoiarib. They are not from the tribe of Judah or the lineage of David! So, Maccabees represents the starting of a political ideology that the Pharisees don't agree with. Levites can't become King in Israel. The Pharisees were at odds with the Hasmonean dynasty as you can see in "Antiquities of the Jews" by Josephus. Book 13.