SikhGiani ji
Thanks for going into more detail. Let me share with you my personal perspective. I promise that I will not smooth things over but potentially make things worse.
You will find elsewhere on the forum where I have stated without apology that Suraj Partap/Prakash should never be used as an authoritative source regarding Sikh history or belief. It is historically valuable as a window on Sikhism in the 19th Century when puratan beliefs were widespread. The contents of Suraj Partap/Prakash are poetry. Many people take it to be an authentic record of events and words spoken at significant moments in Sikh history. They believe that Suraj Partap/Prakash clears up/resolves many questions. I take it to be unreliable as a historical reference, because it was written by Santokh Singh, based on family anecdotes and notes that were kept by father and grandfather, who was a contemporary of Guru Gobind Singh. So for me there is too much room for individuals to add what was culturally and politically important for them to believe. And this found its way into SP.
Having said that, the question remains. Why is Suraj Partap/Prakash used for teaching, explaining the history and precepts of Sikhi? Could not the answer lie in the cultural and political instability in the years leading up to the completion and adoption of the Sikh Rehat Maryada? We know that controversy over the Raagmala split the Chief Khalsa Diwan, prompting Panch Khalsa Diwan to remove itself from the proceedings in protest against "a puratan text." In an attempt to build a consensus among factions, Chief Khalsa Diwan worked in the opposite direction to smooth over differences. The result: sangats may decide whether to recite raagmala, but they may not remove it from the granth. Consensus was important in that era of forging a unified Sikh identity.
Might is not also be the case that Suraj Partap/Prakash was let into gurdwara teaching for exactly the same reason? Frankly I don't know. This is my hypothesis. I do think anyone who has read Sri Guru Granth Sahib Ji and thought about its message would take a skeptical view of Suraj Partap/Prakash as a dependable reference.
I do not think this will happen in the near future.
I think what should be done is that a panthi committee should write sikh ithas using all material we have now so we can fix the errors and everyone can agree on it. also these great works should still be studed.