That may also be because the 3GS is still on sale now. Not many Android phones from 2009 are still available for purchase.

Yes but major features like Siri and turn by turn wont work on the 3GS (or 4), which I think says a lot as well.

Check smackfu's comment for device feature support breakdowns: http://news.ycombinator.com/item?id=4096633

Also worth noting that the identically-spec'd (sans phone bits) 3rd gen iPod touch will not be supported. Unless every single iOS 6 feature was phone and camera related, I can't see any good reason that one should get it and the other won't.

Apple is currently selling iPhone 3GS (free in the states if I'm not mistaken), but thy ceased selling 3rd gen. iPod touches 2 years ago.

The reason iOS 6 supports 3GS isn't for the people who bought one in July 2009. The reason iOS 6 supports 3GS is for the people who bought one today for $0.99.

That's ridiculous. Apple clearly states 3GS here:

http://www.apple.com/ios/ios6/

It says mostly that iOS hasn't changed much in 3 years.