Obviously he was a real person. I don’t think anyone denies that. There’s a big difference between Jesus being a real person and Jesus being the son of God.
Or maybe it wasn’t that they didn’t recognize him, but just that they had no reason to believe he was God. There’s a guy in Miami who claims to be Jesus, just because people don’t believe him doesn’t mean they are denying God’s existence. The big question is, how would you know if God was here? How could you tell the difference between a miracle and an illusion? It’s not that people deny God, it’s just that they aren’t naive and know that it takes some pretty big reasons to believe someone is God.
Would this man in Miami let himself be put to an agonising & obscene & loathsome death for the good of his enemies ?
False Christs never have a cross - the true one does

More than that, the Cross is inseparable from Who & what Jesus is & does & says.
Anyone can fake being God - not everyone can live a life consistently of such a quality that one can account for such a person only by recognising him as numinous - as holy. Most of us are not holy - that is what sets Jesus apart: His holiness; to be holy, is to be set apart. And this is met with in Luke 5, when Peter asks Jesus to leave him. Is your man from Miami like that ? Does he make people feel dirty, ashamed, confused, simply by being in their company ? Jesus does - & Isaiah is equally upset in Isaiah 6. So the Bible can defend itself - for passages like this show how upsetting the Holy God can be, when He confronts man who is sinful.
What would happen, do you think, if you met someone who was perfectly good ? I don’t know about you, but I suspect it would be a very uncomfortable experience. The**
difference** between God Who gives the Bible, & us wretched creatures who receive it, is what makes one think the Bible is the Word of God. Goodness is not always attractive - people rejected Jesus, because what He was, showed up what they were. And so does the Bible: nothing can escape from it, because nothing can escape from Him. It too shows us up.
As you say, people should not be naive.
