When someone in a marketing team of a company sends a message, they usually speak for the company, not for themself, except otherwise explicitly stated. So indeed, we can't expect a huge company like Microsoft have a uniform opinion on all things, but Microsoft as an entity stills sends a more or less coherent message if they take care of their communication.

And I would not blame someone understanding a statement from Ballmer for Microsoft's official stand if the statement was made when he was the head of the company and the company did not issue an apology or a clarification after the fact.