EGW takes the scriptural quote (Is. 28:10) completely out of context. The subject matter of Is 28 is not an encouragement to study, it is a warning to Judah and Ephraim about spouting off false prophecies while they are drunk:
And these also stagger from wine and reel from beer: Priests and prophets stagger from beer and are befuddled with wine; they reel from beer, they stagger when seeing visions, they stumble when rendering decisions. All the tables are covered with vomit and there is not a spot without filth. “Who is it he is trying to teach? To whom is he explaining his message? To children weaned from their milk, to those just taken from the breast? For it is: Do this, do that, a rule for this, a rule for that; a little here, a little there.” Very well then, with foreign lips and strange tongues God will speak to this people, to whom he said, “This is the resting place, let the weary rest”; and, “This is the place of repose”— but they would not listen. So then, the word of the Lord to them will become: Do this, do that, a rule for this, a rule for that; a little here, a little there — so that as they go they will fall backward;" (Is. 28:7-13)
To me, this is an indication that she was not infallible in her interpretation of scripture. The fact that a lot of people just swallow whatever she allegedly wrote without checking the scriptural context is an indication that they take her word over the Word of God rather than the other way around.
No knocking EGW - she was an inspired writer. But an infallible prophet of the order of Isaiah, Daniels, etc? No way.