I believe that young people came out in record numbers because they wanted to vote for someone they could trust.
TM like many politicians before her see no problem in going back on her word. She is not alone in this and politicians have been guilty of this from both the right and left side of politics.
Despite your reservations or views on JC it is clear he has not gone back on his word since being elected as the leader of the opposition. He has stood by his word and fought a campaign based on policies he believed in and refused to use dirty smear tactics.
Perhaps people generally are sick of being lied to and electing politicians that seem to showmen/careerists first and representatives of the people second.