"Just hear me out Harry, Dumbledore is a powerful and knowledgeable wizard and he decides to take a broom to the ministry instead of operating or using the floo network, in second year you had to kill the Basilisk even through the headmaster knew what was happening and could easily kill it and last year a man he knew for so many years suddenly because a death eater in 1981 but doesn't help him get a trial then when he escapes doesn't do anything to help.