Ok, let me paraphrase a little on that. I like to use the phrase (Just Saying) because I think it is like saying: "I'm stating My Humble Opinion eluding (evading) arguement" Or in other words "I said it, but it's just an opinion not an arguement"

Origin is New York Jewish, can't tell you when it was born though, but my guess would be before you were. I'm guilty of the phrase, although I'm not Jewish, only by marriage and not even from NY. but I like it because to me it is saying that I'm stating MHO eluding arguement, but if you prefer then take it to a higher court.