That it means something different than what Jesus taught. You said, if I understand correctly, that Jesus' statement concerning born from above means something altogether different from Peter's statement concerning born again. I think they are one and the same thing, namely, the making alive of the sinner once dead in his trespasses and sins. that is not a physical thing; but rather it is a spiritual thing which Jesus pointed out by is stating, "That which is born of the flesh is flesh, and that which is born of the Spirit is spirit" (John 3:6).
Because they aren't the same thing.
Critical analysis of exactly what was said instead of reading extra concepts into what was said by Jesus is necessary.
Just because the majority of Americans read "you need to be" due to a massive marketing campaign into John 3 doesn't make it so.
You have been duped by the world. Sure they might have had good intentions....but the results are disastrous.
When Erasmus translated this section into English for the Book of Prayers or Evangelion out of Latin the world was just coming our of the "Dark Ages". Much had been lost and he, as well as Tyndale, were following the pattern set by Martin Luther. And where Luther was doing very well....he was not perfect.
This error, as well as many others, have been discovered in the centuries to come as information about Anthropology, Topography, and other writings have become known.
Jesus had good reasons for saying what he did but it is completely different from the concept that Peter is discussing.
John's Gospel is one that focuses on theologies and concepts using narratives to demonstrate truth vx errors which are still being used today.
"Born Again" is an insidious error that removes the truth of God's omniscience. God does NOT react as events unfold....God has already planned and already acted upon them as they do unfold.
There is no "magic moment" in people's lives where they feel a rush of emotions and corresponding physical effects due to them. (They might but it's not common)
God is more interested in FRUITS than emotions.
Just because a peach seed is planted and sprouts doesn't mean I'm going to get any peaches eventually. I might but not necessarily. Jesus was saying that Nicodemus had a role already laid out for him for God and all of Israel. And Jesus was correct. Nicodemus did have a role and it's recorded.
Nicodemus was already a believer....he didn't need to become one. He wasn't hiding for the night time visit. Night is socializing time in Israel where the narrow and tiny streets are lit with torches/lamps and full of people. It still is to this day.