Baptism is as necessary as it says - unless you are baptised, you cannot enter into heaven - why do you question it as though it does not say what it says?
Because of the CONTEXT of the passage. The verse does NOT say born AGAIN of water and of spirit, it says born of water, and of spirit.
If the passage said born again of water etc. you might have a leg to stand on.
Born of water and of spirit in the context of the verses before and after tells us He is speaking of our 2 births, physical and spiritual.
Becky