How could Ellen White endorse what the Bible condemns?

I believe we need to ask seriously whether Jeremiah was describing the Christmas tree or something like it in the passage you quoted. First, notice that though you have identified the wood brought into the home as an evergreen, the Bible text does not do so. It merely refers to a tree.

Second, what then is done with the tree? Are silver and gold hung on its branches? The New American Standard Bible (NASB)—a conservative and quite literal translation—renders verse 3 this way: “The customs of the peoples are delusion; Because it is wood cut from the forest, The work of the hands of a craftsman with a cutting tool.” It doesn’t take a craftsman to cut down a tree. Even I can do that! So why a “craftsman”?

I believe the reason is that after felling the tree, the craftsman carved it into an idol, which the people then decked with silver and gold. This carving of an idol—not the mere cutting down of the tree—required a craftsman’s work. Verse 5 actually makes this quite explicit. Again I’ll quote from the NASB:

Like a scarecrow in a cucumber field are they, And they cannot speak; They must be carried, Because they cannot walk! Do not fear them, For they can do no harm, Nor can they do any good.

This is describing an image, a representation of a god, and comparing it to a scarecrow, something that you shouldn’t be afraid of! Isaiah 44:9–17 presents a parallel picture, but with more of the detail.

Despite the superficial similarities, Jeremiah 10 is not describing a Christmas tree nor what people do with a Christmas tree. I have seen people in a Catholic church genuflect before the images and before the altar as an act of respect and worship. But I have never seen anyone offer any such homage to a Christmas tree, and probably you haven’t either. So having a Christmas tree in the church is not an issue of false worship. Mrs. White, who you have believed was a prophet of God, also recognized that it was not a matter of false worship. Shouldn’t we accept her writings when they harmonize with the real meaning of Scripture, as I believe they do in this instance?

See also the preceding question and answer.