At first you might think that he fears the Pharisees' murderous plot, that he's trying to duck them to save his skin. But knowing Jesus, that can't be it. Does Jesus ever try to save himself solely for survival's sake? He has completely surrendered himself to the will of God, whether it is ministering to others during his life or submitting to death when the appointed time comes. Asking that people keep his activities a secret couldn't be an act of cowardice.
Maybe that's why Matthew inserts this prophecy from Isaiah foretelling that the Christ would come as the suffering servant. God is pleased to send him among us clothed in meekness and humility. Sure, he could easily smash his enemies, triumphing over them and putting them to shame, but instead he is patient, humble and merciful. According to Isaiah's prophecy, "He will not quarrel nor cry out, nor will anyone hear his voice in the streets." He's not a rabble-rouser. He doesn't accomplish the will of God by arguing and protesting, trying to get the last word in. The Pharisees display a worldly zeal for verbal sparring, seeking to score points against Jesus in the public eye, but Jesus chooses to disengage from the conflict and withdraw.
Jesus will not rise to the bait of the Pharisees but he will stoop to identify with the lowly and downtrodden, the people whom the teachers of the Law have relentlessly beaten down. "A battered reed he will not break off, and a smoldering wick he will not put out." A battered reed has been bruised; a smoldering wick is weak and faint. These are images of the spiritually poor whom Jesus seeks. He doesn't come along and finish you off when you're on your last gasp. He doesn't kick you when you're down. Only the gentlest of hearts knows how to nurse that bruised soul back to health, or coax that dying flicker of faith back into a bright flame.
The contentious person has no use for Jesus and the brawler holds his meekness in contempt, but that hardly matters. Jesus only concerns himself with the humble who have no strength to fight any longer, who know they have no argument before a holy God. It's only when they've given up hope in themselves that they find their hope in him.