In short
Matthew describes Jesus as the one who is called Christ
with a positive rather than a negative purpose. This repetition of Jesus as the Christ at the end of the genealogy stresses how much greater he is than all his ancestors, and the fact that Christ
was his office and title.
He is said to be called Christ
not because Matthew does not recognize Jesus as Messiah himself, but to indicate that he is greater than all the others mentioned (see Matthew 1:1). Over and above his own name Jesus also carries this special title indicating his office. Here the purpose is to emphasize that office, and therefore this addition to his commonly used name is also necessary.1
12 And after the deportation to Babylon: Jechoniah was the father of Shealtiel, and Shealtiel the father of Zerubbabel,