Tom Robertson found out that the openXML criticisms had no backing.
The press also quotes him: "Interoperability is an issue that we vendors should deal with, not the customers" and added “Interoperability is going to be a feature in a product, which customers demand. It is going to be a standard functionality, just like security.”
They also stress that Microsoft has nothing against ODF, the existing ISO standard for office productivity applications, as the company supports converters. They "don't reall oppose ODF".