While I agree with the rest of your post, they do have a legal reason. Someone buying a product in a country not supported by PSN and then running into issues, can create legal problems. They have a few very specific lines in their ToS to address just that. All of these companies do.
Here's the thing. In order for a service like PSN to offer its product/service in a country, it needs an agreement with the government of said country. They can't just open a store and do business without a contract. It gives them a legal cause to POTENTIALLY (read, not very likely) not allow it.
But as I said in another post, there's just a possibility that it might happen. You're 99.9% safe. But there is that tiny little possibility that Sony might pull the plug.
@Yuniac
The game did not demand the creation of the account but it was in the games requirements. Which means there is no legal issue here. Sony specifically mentioned it. The fact that people didn't read that, means nothing. It's like as ToS. It's enforceable even if you don't read it.
It being immoral is another issue. Doing this AFTER selling the game, despite technical issues, is a whole other level of messed up.