Scripture isn't a smokescreen, it's quite clear. Your repeating question, however, is a deflection and doesn't invalidate scripture.
Questions of the type "show me where specific person x does specific thing y to specific group z" have little value in Bible study.
It's like someone asking "show me where Jesus told someone homosexuality was a sin" to deflect from scripture showing homosexuality is a sin. Or like the person asking, "where specifically does the Bible say "Trinity" or "show me where Jesus Himself directly claims to be God" to deflect from verses proving that Jesus is God.
Any study should focus on what the Bible says, not ignore what scripture says unless it fits a specific personal wishlist. If The verse says Jesus is the propitiation for the sins of the whole world, not just believers, then it is God-breathed and the 'audience' doesn't change the teaching that Jesus died for the sins of the whole world, not just the sins of believers.
Paul speaking of his past preaching of the gospel that Jesus died for our sins to the Corinthians before they had received the gospel is clearly a case of unbelievers in the past having been told that Christ died for their sins. That Paul is speaking to those Corinthians who did receive that gospel, and not at the moment to those who did not receive it, doesn't change the content of the gospel which he had first preached to them.