He was running huge events which caused servers to crash over and over and over by getting thousands of people into single zones.
his ban was reverse because while yes he did crash the servers, and caused a big riot by encouraging people to cause havoc, and then once it started getting bad tried to convince people to stop, but it was too late.
blizzard decided to revert the ban simply because yeah it was not intentional, and was a big community event.
but yeah none of these bans are permanent, they are 2-31 days