Why did Jesus want to be baptized?
Oftentimes the simplest answer is the correct answer. One would think that Jesus being baptized by John (the Baptist) would destroy the Church's idea of Jesus's "perfection" - but no - not if the Church or her religion had the final say (and they did for 2000 years).
"John [the Baptist] appeared, baptizing in the wilderness and proclaiming a baptism of repentance for the forgiveness of sins." ~ Mark 1:4
"In those days Jesus came from Nazareth of Galilee and was baptized by John in the Jordan." ~ Mark 1:9
According to Josephus the historian, John called for Jews to seek God for forgiveness and vow to show unending kindness toward one another, and to walk humbly God - things John saw lacking in his generation - then baptizing them so that the cleanliness of their outer parts would symbolically match the cleanliness of their forgiven and changed inner parts. The person being baptized had already repented for the harmful acts they committed, and it was understood (by Jews) that the person being baptized was already forgiven.
Why then did Jesus want to be baptized?
"As Jesus was setting out on his journey, a man ran up and asked him, 'Good teacher, what must I do to inherit eternal life?'. And Jesus said to him, 'Why do you call me good? No one is good except God alone.'" ~ Mark 10:18
Yeshua (Jesus) repented, and he was forgiven by God, and he went to John to be baptized because he recognized his deficiencies as a decent human being.
When God began to walk with Yeshua, he knew he was forgiven and this experience humbled him - as being forgiven by God humbles you because of the way God treats you from that point onward.
The God of Yeshua then is the same God of Yeshua now. Forgiveness is a perpetual deed and act.
Yeshua clung to the Laws of liberty and human decency and not the laws of Moses (certainly not those parts which contradict the Laws of liberty and decency).
So Yeshua didn't go get baptized because he plucked heads of grain on a Saturday or because he partied with prostitutes and refused to perform religious fasts - he had long since been forgiven.
Wisdom is earned. He went because there were times in his life when his only focus was himself and he treated people like shit. "Why do you call me good?" (Such a question requires introspection and a ton of realizations, and Yeshua both taught and teaches from his experiences.)
The church, and the Matthew, Mark, and Luke gospel writers were uncomfortable with Yeshua's baptism and - being the religious spinners they were - they turned his baptism into a mystical event (spirits, voices, and doves), whereas the gospel of John, though mentioning John the Baptist and the mystical elements of previous gospels, leaves out the baptism of Yeshua altogether. "Enough time has passed, so let's just act like it never happened." ~ Gospel of John
Though Yeshua may now be as close as one can get to being "good", he certainly wasn't back then.
He learned and understood mercy and human decency because he experienced mercy and decency from the Living God - and he exclaimed this merciful power to a faithless unrepentant godless generation.
It is an amazing thing then that God never required perfection from us in order to save us from godless despair and death. God never required faith from us in order for God to be faithful. God never required mercy from us in order for God to be merciful.
The church thoroughly destroyed itself and erased any good and decent knowledge of God it once had; this is evident in their scriptures.
Any understanding of salvation was gone - though forever visible in the salvation of Yeshua - their Jesus became such a perfect idol that they did the religious spin on salvation (being aware of their own despair, perceiving their own demise) and turned salvation into an afterlife and a lie, exchanging the faithful power of God for absolutely nothing. Any mercy from God would have to wait until after you schemed and fought your way through this hell and finally dropped dead.
Or maybe on some future date, there'll be a rapture - some time in the distance where God is finally, at long last, not an evil uncaring bastard and poor excuse of a "father". This "salvation" was always a worthless lie and has added no good thing to this world.
God is not with you, not right now. You receive no good and eternal thing from God, and you have the same portion as everyone else in this place. Your fears and your despairs are your testimony.
When you see God walking with you, I'm telling you, you won't need any book or lengthy sermon to tell you that God loves the world.
