Deciphering Slang and Slinging Catch-phrases

Is "just sayin' " really "a way of defanging — disingenuously, perhaps — a potentially confrontational statement"?

I, who am of course too old and out of touch to know anything about slang or cathcphrases, would have described it as nearly the opposite of that -- a way of signaling ones opprobrium more clearly while at the same time indicating ones lack of faith in the listener's ability to recognize the justice of that disapproval, or to effectively change.