They interview the player/person, what they stand for is their own prerogative. It isn't up to Blizzard to dictate what people should think or are allowed to say on issues such as human rights. It is their right to ban someone for what they deem 'misconduct' though, so yes they are in their rights doing what they did here.
They will also have to deal with the consequences of that decision, a lot of people are cancelling their subscriptions and deleting their blizzard accounts.
This will probably not impact them much, but hopefully there will get big enough that it does.