I would think in their defense of claiming him both god and man, that they would sell his humanity a little more.
Now, thinking on that.... where is his story for the years between toddler and adult? Oh well, back to murder hornets!
Christ wasn’t sold, as God’s only begotten son he was given into death and resurrected that man might enter eternity.
Romans 6:3-4 King James Version (KJV)
5 For if we have been planted together in the likeness of his death, we shall be also in the likeness of his resurrection:
2 Corinthians 5 New Living Translation (NLT)
1 For we know that when this earthly tent we live in is taken down (that is, when we die and leave this earthly body),we will have a house in heaven, an eternal body made for us by God himself and not by human hands.
2 We grow weary in our present bodies, and we long to put on our heavenly bodies like new clothing.
3 For we will put on heavenly bodies; we will not be spirits without bodies.
I assume by "they" you mean Christians, right?
The thing is that some later, 2nd century sects tried to downplay the "man" part but that ruined much of what made Christianity, well, Christianity.
There is a lot about his humanity - and the years between 12 and 30 years are quiet, but that's pretty descriptive about his humanity by its very silence
The reason the first 30 years of Jesus' life are largely left out is that it simply isn't the intent of the authors. In fact Mark and John don't even have the birth story. The gospels are not purely biographical- at least not in the modern sense
Remember - until 33 no one think this guy is God, that's not even something that would cross their minds (in a 2nd temple Judaic mind).
I think it is very telling that there are no embellishments about Jesus' life between 12 and 30 -- those would make it like the other "epic lives" of deities like Krishna, Rama etc. who have embellishments put in.