I think Forex trading is available for all countries. They just limit it for the regulated companies and not allowed the unregulated broker to accept clients from the country itself.
The 1st world countries do not have any restrictions when it comes to Forex market investment unlike the 3rd world countries that prohibited their people and brokers to accept clients from them without regulation.
The first world countries are very rich and they can trade anytime they want. Apart from it, they do not have restrictions on it unlike to the 3rd world countries.