I agree. I think this is a logical explanation of the passage. He sounds like he's being facetious, trying to make a point, and I certainly can't draw the conclusion that the point he was making is that baptism is unimportant, considering the context of other scriptures.
Paul did teach on baptism:
Colossians 2:12 Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead.
Romans 6:3 Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death?
Romans 6:4 Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
Romans 6:5 For if we have been planted together in the likeness of his death, we shall be also in the likeness of his resurrection:
Acts 19:3-6 And
he said unto them, Unto what then were ye baptized? And they said, Unto John's baptism.
Then said Paul, John verily baptized with the baptism of repentance, saying unto the people, that
they should believe on him which should come after him, that is, on Christ Jesus. When they heard this, they were baptized in the name of the Lord Jesus. And when Paul had laid his hands upon them, the Holy Ghost came on them; and they spake with tongues, and prophesied.