Jesus was hailed as the messiah
The supporters of Jesus called him the messiah (or Christ) because they believed that Jesus was the long expected messiah that had been promised by God.
Christianity is the only religion on earth that has felt that omnipotence made God incomplete. Christianity alone has felt that God, to be wholly God must be a rebel as well as a king. - G.K. Chesterton
The people believed that God would send a messiah
The Jewish people believed that God would send a messiah. The word messiah is Hebrew for 'anointed one', this is Christ in the Ancient Greek language of the time. There are lots of different groups of people who could claim to be anointed for their job but the word messiah was reserved for royalty and in particular for the coming liberator of Israel.
Lots of ideas about who the messiah would be
There were lots of different ideas about the messiah and what that messiah would do but the majority believed that he would get rid of the occupying Romans and start a new government of Israel. They expected the messiah to act in the same way that Kings had done in the past.
So Jesus confused them
Sometimes what causes us the most confusion is not that something is happening but that something is not happening in the way that we expected it to.
If we were a god who had promised to send someone to put things right for your people you might think that the best way to do it would be with force and great glory. An overwhelming force that drives the point home in an obvious and blatant way. The kind of way you want your favourite sports team or player to win all the cups and championships - with ease. It then gets very uncomfortable and confusing when things are not working out the way you wanted them to.
When Jesus was proclaimed as the Christ by his followers it caused confusion. Why didn't Jesus behave like a messiah and set Israel free?