Explain the irony that emerges at the end of Gulzar's story " Michelangelo"?

Michelangelo written by Gulzar us based on the life of Italian sculptor Michelangelo who painted the Sistine chapel.

In the story Michelangelo is seen as an eccentric who does not carve statues according to rules, rather makes his own perception of character's looks. He draws them from faces of real people who seem to fit the character from his viewpoint.

Towards the end of the story, we see Michelangelo has finally found his Judas in whom he had been searching for so long in a man named Marsoleni.

Ironically, the man turns out to be the same person whom he had once painted as a baby Jesus. This might be a personification of the pure and evil both of which resides in human.

The innocence one has as a young child fades away with time as betrayal and greed fills his heart.