Originally posted by: FlauntPessimism
The main issue with assuming that there was no Sati of Madri is that there is no mention of how she died if not while committing Sati. While the death of Pandu is clear, it's only the dead body of Madri we encounter if we exclude the portions of Sati. I therefore can't completely ignore the Sati probability unless Madri herself was an interpolation.
Coming to your second point about reasons of interpolation, there is an instance of beef having been prepared in Rishi Shaunak ashram when Ugrashrawa visited them, this verse isn't the part of main CE and they feel it was an interpolation. Now you could yourself think what benefit would an beef preparation episode do? Yet it was interpolated. Again the details of Dravidian kings seems an interpolation same as the visit of the king of Tripura, so I wouldn't say that interpolation only happened because of some use.
Aside if it wasn't permissible for a woman to have more than 4 partners excluding her husband and Kunti actually bore all five of them(excluding Karna) then definitely she had at least 5 partners excluding her husband, and thereby becomes a bad character woman as per the standards of those days so to save her respect an interpolation of a second wife who gave birth to two of them of them does become important
Although I myself don't think that Madri could be an interpolation but that could be a way to look at it.
About the Sati part, while undoubtedly Jauhar was something that started with invasions, attributing Sati to invasion is nothing but a sense a false pride that we were great and stayed in utopia until some outsiders destroyed us
You wouldn't believe I actually came across a person who said there is nothing as preVedic because Vedic verses have been existent since eternity. When I asked if that was the case why is Manu, Mandhaata, Divodasa etc. Mentioned as humans of past the response was that a adharmi like me can never understand the Vedas
There was another claim that Sreemad Bhagwatam is millions years old