Only person I've heard use a more contrarian tone is Sant Gyani Gurbachan Singh Ji. They mention the Quran being stolen letters that Muhammed appropriated by murdering the author. They also mention the origins of some Islamic customs as being not so divine. I don’t know what sources they would be using in that era, it would be interesting to find out. I think one factor why our parchariks aren’t critical of Islam is lack of actual research and available material. I doubt Gyanis have access to the kind of material Christian theologians have. Other than that, post-47 we don’t see Islam as our main threat. Nevertheless, the older generation continue to harbor mistrust of Muslim. It’s just the generation post-47 that grew up with a romanticised version of Islam, started displaying  “enemy of the enemy is a friend” attitude.  

You   better behave 

Curiosity. And a katha I was listening to. That's ^^^ what I consoled myself with until I realised that Muslims themselves defend these historical accounts and events; they don't deny them. Sure, they try to re-frame and re-contextualise them (whether they do so in good faith or for other sinister reasons is another debate), but they never abrogate them. Why are we, as Sikhs, arguing that Muslims don't know their religious history, and we know better than their own sheikhs and historians do? Again, this theory would only hold water if Muslims themselves refused to acknowledge their accepted account of Islamic history. But not only do they accept it, they vigourously defend it.

What has prompted this thread? is it possible Islamic history has been distorted by those with an agenda to justify their own actions, by using  examples based on their Prophet’s  life? maybe a lot of the controversial things written about didn’t actually happen   

... while actual Islamic teachings and scriptures (The Sunnah, the Quran and the Hadiths) make no attempt to conceal the frankly questionable feats, bachans, and moments of his life? Rampant sexual degeneracy, idolatry, hypocritical religious edicts and conduct, and unexplainably savage and bloodthirsty barbarism across the board. Yet, Sikh sants, gianis, and parcharaks speak so effusively and warmly of "Mohammed Sahib" and his various companions and successors. These Sikh personalities can barely conceal their admiration for the Islamic prophet and his achievements.  What's going on?