It’s hard to prove Judaism has been subverted in our time because those claims which made it most vacuous are kept out of the books. You can find such travesties as Mechiras Chametz and hair like hair-coverings in the Poskim, but the very worst heresies are only passed on orally, like in a cult, especially to those who fall afoul of them.
This is why it’s harder to find written evidence on the regular bookshelves of Chassidic and Mussar antinomianism, the esoteric meaning of the “Chadash assur min hatorah” catchphrase, Brisker doctrines on denying reality (such as the infamous “Am Ha’aretz chicken” story) — among other things, and many more.
For a “book-based” nation, it seems strange there are important customs that somehow manage to evade a well-written exposition. Like the “holy” battles of Rabbi Shach against half of his contemporaries, Rabbi Yoel Teitelbaum‘s view (adopted by other fools “in principle”) Eretz Yisrael is only for Torah scholars (Only Teshuvos Vehanahagos writes about this a bit, because he lacks the horse sense to realize this doctrine contradicts entire parshiyos in the Torah, see the parable here).
Like the “insight” Yeshiva youth need not (and therefore ought not) observe the Torah they are busy studying (which has nothing to do with the Dinim Vehanhagos sometimes looped in on this!), hinted at throughout the “Tenu’as Hamussar” set by Rabbi Dov Katz (such as reading Shema at its proper time or covering the tables on Shabbos (which has nothing to do with eating, as they are covered on Yom Kippur, as well), or eating only truly kosher food).
Like the notion, all mitzvos are capable of observance without their numerous, peripheral “Tzitzin” of halachic “side-constraints/conditions” leading Judaism away from “legalism”
Chazon Ish – Emunah Ubitachon, end of chapter 4:
והתמדה בדרך הדביקות מצד אחד וההזנחה בתלמודה של המצוות מצד שני, יוצרת שיטה שלמה הנראית לרבים, ומתבלטת כיצירה מסוימה, המכרזת על עצמה, ועל אלה המתיחסים אליה, כאילו אמרו חלילה הרינו מקבלים עלינו מלכות שמים ע”מ שאין עלינו דקדוק הדין.
וההכרזה הזאת הלא היא מחמורה שבחמורות, חבר הוא לפורקי עול, ולא עוד אלא שהקבלה על הדברים שהם נכנסים במחיצות קבלתו מזויפת בהחלט כאשר סיג וצרורות של המראה מעורבות בה, עירוב מכוון ומבוסס, מחושב ויסודי.