No, you missed the point. “We” do not purify “ourselves” but it is through Christ that we are purified. The stains of sin are purged before full union with God. God does the purging.
Here you falsely conclude that because a Scripture reference is used to support Purgatory that all doctrine is derived from Scripture. In the Protestant world it might be the case that doctrine is derived from Scripture, but not in the Catholic world since much of the belief was handed on before the scriptures were written. Scripture itself is something that was handed on.
You make it sound like someone cracked open a bible, found a few random passages, and came up with a doctrine (which, ironically, is precisely the tendency in Protestant/Evangelical churches). Rather the passage in Maccabees is used to support the idea that purgatorial concepts existed in Jewish culture and were handed on into Christianity.
Let us also be clear that “The Apocrypha” includes several books not in the original canon of 73 (the one Luther had foresaken and Catholics still use today) in which the Catholic Church holds that those books outside the canon but in the Apocrypha are insightful but nothing more than that. Apocrypha is a broad term.
Did you know that not only did Luther remove the deuterocanonical books (the ones you call Apocrypha), but he also wanted to remove books in the NT such as James because he couldn’t reconcile the faith and works passages with his theology? I don’t know why people get all excited about Luther, a single man who thought he knew better than centuries of scholars and wisdom. I certainly wouldn’t trust someone that suddenly knew better than everyone else and wanted to eliminate various parts of the established tradition simply because it didn’t fit his view of the world.
Also, your reference to the idea of purification not being new to religion brings nothing to the argument. The concept of a virgin-born god also is not new and predates Christianity by a longshot. So, what’s your point? Heretics, such as Luther, also weren’t new to Christianity, but he happened to exist at just the right time and place culturally for a big movement to take place.