Android - Why is Google Maps telling me that Offline Maps aren't available?

It turns out that just because you can see and use a map online, that doesn't mean that Google will allow you to make the area available offline.

Offline maps are only currently available for certain countries, and Brazil isn't currently one of them, in fact it seems to be a fairly odd selection.

Google have published the full list of countries that it's available in here: Maps for Mobile - Offline Availability

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EDIT: note that in a July 2013 Google Maps update, Google made offline maps into a hidden feature with no menu option any more. More about how to make maps available offline here: Get offline maps in new Google Maps

I found that I was able to remove the version of google maps I had installed (which was 6.11.1) and downloaded and installed an older version (6.6.0) from here which allowed me to pre-cache the area I was previously not allowed to. But in the older version I had to go to settings,labs and turn on the pre-cache option and then long press on the map, click on the balloon, and then scroll to the bottom for the pre-cache option.

I don't understand why downloading maps of certain areas is not allowed in newer versions. Obviously its not a technical reason. Is there some sort of political or legal reason? Other map apps can download maps for the entire world. It really doesn't make any sense to me...