Do brand/organization specific tags such as amazon or microsoft provide any value on Meta Stack Overflow? I think they should not be allowed otherwise we would be opening gates for all kinds of tags such as samsung or nokia and others.
On Meta they make sense. There are questions about the impact of the given company on Stack Overflow, and the questions about something having impact on Stack Overflow belongs to Meta. Because the impact is caused by the phenomenon called Amazon or Microsoft in that particular case, so are the amazon and microsoft tags on place.