Was it actually Alexander that did this?
lots of theories
1) revenge for the burning of the acropolis of athens
2) he got drunk
3) perhaps it happened as a ritual to indicate a change of king
He wanted to set an example to make sure the Greeks don't rebel in the future. He got all his evils out the way so he can do good later.
>>3154355
fpbp
Basically we aren't sure, these are the prominent theories, and rights will tend to favour one or another based on their own bias and interpertation of Alexander's character