1st to mention one important thing- Ray Allens patriotism should not be in question as he already won a gold medal while wearing USA jersey (one could argue that he was best player that year, mostly cause he was young and could handle playing w/o vacation).
Now personal expirience, as Croat I always felt shame when our NBA players refused to play for national team because of the need for rest (some of them were celtics, Radja, Vrankovic etc.) but I ve had first row seat to what preparation for it looks like, and then changed my opinion:D
Watching 15 guys sweat in the middle of summer in closed gym to get to some resemblance of team spirit, team strategy or just some simple plays from the book. It is hard work, and you can't just lazy your way into team and just play games.
Your body needs the rest, and more importantly players need some mental rest as well, giving your 100% in any team sport can't compare to giving 100% monday-friday 8-16 office job most of us do with sight on first next weekend we ll try to get hammered (usually while watching these same athlets on TV while doing so:)).
The point that hurts players is not that they provide their services for free, it is that someone is getting big money out of it, and it is not their country or the organization they come from. Its some comitee full of foreign old men preaching what an honour it is to play for your nation while laughing at Cuban and C's owners for having to pay big bucks for product they get for free.
(wow this rant ended up longer than I expected, sorry)