….. ‘reading ones own ideas into a text’. Regarding David’s conception, I would have to mention Deuteronomy 23:2 ,

“A mamzer (H4464 bastard) shall not enter the community of יהוה, even a tenth generation of his shall not enter the community of יהוה. " Scripture is explicit when someone is born of a concubine or illicit union (Jephthah in Judges 11:1–2, Abimelech in Judges 8:31) David’s case shows none of that language. It seems clear to me that David is merely expressing the depth of human fallenness and not confessing his mother’s sin. “Jesse didn't even seem to consider David one of his sons” …. Jessie replied “There is still the youngest,” when asked if there were any others. The word “youngest” is Strong’s H6996 קָטָן small, young, unimportant ….i.e. “the baby of the family”. It seems Jessie speculated and came to a conclusion, just as Samuel did upon his arrival as noted in 1 Samuel 16:6,7 he saw with his flesh, just as Jessie concluded that David wasn’t in the running, being the baby of the family etc.