Official means nothing nowadays given that experts are leaving their standardization bodies in protest. Norway: http://www.noooxml.org/forum/t-93970/norwegians-leave-their-standards-body-in-protest
Brazil, etc.

The national international standards organisation bodies? Does that even make sense? I assume you mean groups like these: http://www.iso.org/iso/about/iso_members.htm These are usually quangos with a few government bods, state funding and a load of industry people. They are do not express the opinion of the government, and thus ostensibly of the people of the nation. They express the interests of a select few companies with offices in that country with the resources to participate. These declarations are from departments of governments themselves and in democratic terms at least have far more legitimacy.

Despite what is suggested these individuals are not repesenting the national ISO bodies of those countries nor are they people supervising those national ISO bodies. 

The people signing this letter are purely officials working for different ICT organisations (representing them often in regards to free software) within those countries and their statements are not nescesarily representing the country or the ISO national bodies views. 

The represented view by those people is more the view of some free en open software organisations than the view of countries.

that if you want to use a published standard for your documents:
ODF compatability is available on MANY applications
OOXML compatability is NOT available from Microsoft products.