When Jesus occupied the Temple – with the backing of a million pilgrims- it was an implicit claim to be the true leader of Israel. No wonder the temple authorities wanted to get rid of him.
P.S. I only recently noticed that when Jesus threw out the traders he also threw out their customers!
Jesus enters the Jerusalem temple so publicly because he finally makes it very well known that he is the son of God, the Messiah . He knows his mission will end soon.