Why did Alexander the Great burn Persepolis?

Classical historians were consistent in their claim that the burning of Persepolis was the result of a drunken party that turned bad. Twentieth-century historians have encouraged us to think a more broadly and to consider other factors that may have played upon Alexander's mind. This homework task supports student understanding of the NSW Ancient History syllabus
Higher School Certificate course
Part III: Personalities in Their Times
Option H: Alexander the Great
Why am I never invited to these types of parties? Preparing too much time preparing for Ancient History classes?