Dear Dr. Shabbir, Assalamu alaikum.
I really appreciate you for asking such a humble question to tell you your "great blunders".
I will point out just one mistake in your approach (I do not want to use provocative word like "great blunder"). You made a big mistake is writing a book with provocative title like "Criminals in Islam" showing hatred towards past scholars while Quran request you to invite people towards Islam with wisdom, kind words and beautiful preaching (16:125). Using provocative titles and words (including purposefully spreading a term 'Mullas' to express contempt) has no place in Islam even if they deserve the same. We shall only let people realize how their view contradicted the teachings of the Quran. Also we must bear in mind that, many of the past scholars were actually had no personal intention to mislead people - they were actually misled instead (they sincerely considered their beliefs as true). One of the major historians of the 10th century CE Al-Tabari states;
"Let him who examines this book of mine know that I have relied, as regards everything I mention therein which I stipulate to be described by me, solely upon what has been transmitted to me by way of reports which I cite therein and traditions which I ascribe to their narrators, to the exclusion of what may be apprehended by rational argument or deduced by the human mind, except in very few cases. This is because knowledge of the reports of men of the past and of contemporaneous views of men of the present do not reach the one who has not witnessed them nor lived in their times except through the accounts of reporters and the transmission of transmitters, to the exclusion of rational deduction and mental inference. Hence, if I mention in this book a report about some men of the past, which the reader of listener finds objectionable or worthy of censure because he can see no aspect of truth nor any factual substance therein, let him know that this is not to be attributed to us but to those who transmitted it to us and we have merely passed this on as it has been passed on to us"
Quranic view of the people of the past is just "they have what they earned and you will have what you earn". People like Allama Iqbal and Allama Parwez never used any provocative words for past scholars. As for Parwez, I remember reading, when he had a serious objection to the interpretation of a verse in Quran by some past mufassereens, he only said "they have translated that verse in a different way and "thus created a difficulty for themselves”!.
Anyhow, my intention is not to cause you any difficulty. If moderators find this post objectionable, there is no need to publish.