It does not really matter what is law for those doing those deals – they just do because they can – almost any western country has sold arms to SaudiArabia – i wonder when ISIS will start shooting with the latest German G36 rifle (ammunition is compatible with M16 by the way).
The solution to this problem would be – consume less or no oil and gas.
This would stop the money going from almost everybody owning a car or flying a plane to big-oil and big-mafia.
When we buy petrol – we fund terrorism.
Another reason why renewables are reasonable – do not always make your decisions dependant on “the money” – or we will get nowhere.