There are some countries were you can pay but not receive funds and some where you can sell but can't keep any money in your PayPal account (it's automatically transfered every day to you local bank account).
PayPal wants to do business everywhere it can (that's how they make money) and modifies how it does business to meet the laws it must.
So, it can't do business in countries where the US prohibits it (see the OFAC list) as they're a US company and limits account functions where other laws require it.
You would need to read your country's law books, which may differ depending n whether you are from South Africa, Japan, Romania or anywhere else where you can use Paypal.
