So I ask him why and he says 'for the same reason we don't ship to Thailand or Brazil' and he goes 'ok?' in the most rude way I can possibly imagine.

I coould not believe my ears and I could not even come up with the answer and he hung up on me.

I'm so upset.

Last time I checked, Singapore was one of the safest and most advanced countries in the whole of asia, granted we are a little small. He didn't even give me a chance to explain. He was so nasty about it too. Maybe he's had bad experiences with hoaxers, but I'm so upset really. even after typing this out I feel like crying...
I'm really sorry you are upset, but as a business that does a lot of shipping, some international, Singapore is on of the nations that is flagged (at least with the companies I deal with) as being an originator of many online scams and fraud. I don't know what to you tell you as a way to get around it.

I've had this with Mexico too. My brother in law lives in Mexico, and we attempted to use paypal so he could send some money up to help his disabled sister, who we help take care of. Paypal suspended the transaction right away, just because of the origin. It was a real pain and I am still not sure if he ever got his money back after I cancelled my side of it.

good luck,
I.