Especially in comparison to other Jews in academia, with similar heresies?
Well, his students at the university once asked him if he was ordained as a rabbi, and he gave a very sad answer: “I never once entered a Yeshiva“.
(Of course, “Yeshiva” does not here refer to a physical building or hierarchy; many Torah greats didn’t go to Yeshiva, such as the Chazon Ish, or barely went at all, largely learning under individual scholars and with study partners. His point was, autodidactic Leibowitz neglected “Shimush”, and had no competent teacher — his parents don’t count.)
Quoting “שבע שנים של שיחות על פרשת השבוע” p. 325:
בקרב הסטודנטים רווחת השמועה כי בנוסף לתאריך האקדמיים הרבים, יש לך גם סמכות רבנית. בהתחשב בעובדה שהיא פנתה אליך לשמש לה פוסק, האם אפשר לקבל ישירות מפיך אישור או הכחשה לשמועה זו?
מימיי לא דרכה כף רגלי בישיבה.
In other words, he came from “the outside” and then drew near. Others, by contrast, have no good excuse for drifting off and becoming “Doctors”, (without naming names).
This is not to say Leibowitz was generally justified in not drawing closer! But still, when YL is right, it’s to his credit (not to mention his useful scholarship when it comes to history, philosophy, chemistry, etc., no worse than “Chochma Bagoyim”). And when he’s wrong (some leftism, etc.), it’s not his fault. Even when flat out wrong, he’s not easy to refute. Besides, he even has the benefit of being the highly-useful-to-society crank mentioned earlier.
To quote:
The vast majority of respectable economists have always scoffed at the crank without realizing that they are not really able to answer his arguments. For what the crank has done is to take the inflationism that lies at the core of fashionable economics and push it to its logical conclusion. He asks; “If it is good to have an inflation of money of 10 percent per year, why isn’t at still better to double the money supply every year?” Only a few economists have realized that in order to answer the crank reasonably instead of by ridicule, it is necessary to purge fashionable economics of its inflationist foundations.
For example, Leibowitz argues (רציתי לשאול אותך, פרופ’ ליבוביץ p. 152-155) there is no such thing as the laws of Tzni’us (later echoed by Nadav Shnerb). But his supposed “proofs” show the inconsistency and inadequacy of modern Poskim!
Also, I strongly suspect he was was not always stating his own, true view, for various reasons. I believe he was continually trying to show how much could be subtracted from what we call “Judaism”, without taking its life (אבר שהנשמה תלויה בו).
Most important, Leibowitz kept Mitzvos.