I always wondered why not say that David _did_ sin but "kol haomer sDavid chata aeino ela toah" is going on the fact that David did teshuva and it is not permitted to remind one of a sin done by a ba'al teshuva It is now a new David and _he_ did _not_ sin
I want to point out that "kol haomer sDavid chata aeino ela toah" is one part of a smiliar series in Masechess shabbos 55b&56a,b. The list includes Reuven ben Yakkov, bnei Eli and Shlomo Hamelech etc.
The strange loshon which you pointed out seems to mean, that indeed there was some form of chait, but not the superfical understanding of the possuk. (This idea is found in Rashi and tosfos regarding bnei Eli.)
R' Yehuda
I understand that the rishonim have many points of view on this question
I just wanted to suggest an additional idea that I haven't seen anywhere but would be happy to find a "makor" for
What to you think of my idea?? That the pashut psat is the chait but we are prohibited from saying it.
reuven
As Rabbi Landy pointed out, "Kol ha'Omer... Eino Ela To'eh" is one part of a series of similar statements in Maseches Shabbos (55b-56b). It is clear from the Gemara that it is not emphasizing that the people in question either repented for their sin, or sinned but we may not discuss it. Rather, it means that the people listed there did not actually sin the sin that one normally would think they sinned.