“R’ Schwalb was alos criticizing MO (TuM) rejection of the austritt principle, which is so central to TIDE.”
The reason MO rejected Austritt was that its intellectual founders were Rabbis Reines, Weinberg, and Soloveitchik. Rabbi Reines was from Lithuania, and Rabbis Weinberg and Soloveitchik were from Poland, where the previous generations of gedolim had never adopted austritt.