If you invest in a foreign bank you are subject to their financial rules and regulations. If you put your money with their CD it will be converted to UAH (grivna) and you will be paid back in UAH, which introduces the exchange rate riskexchange rate risk.
FDIC is not the only reason why a CD in a US bank pays a lower interest, but it could be seen as a contributing factor.
It all comes down to risk and what the bank is willing to pay for your money, when a bank issues a CD they are entering the debt market and competing against other banks, governments, or anyone looking for money. If the yield from lending to one bank is the same as the yield of another, the logical choice would be whichever loan is less risky. So in order for the riskier bank to receive loans they must entice investors by offering a greater rate of return. In addition, if a bank isn't looking for loans they might be less inclined to pay for them. - See "What is the “Bernanke Twist” and “Operation Twist”? What exactly does it do?What is the “Bernanke Twist” and “Operation Twist”? What exactly does it do?"
If your looking to invest in the CD's of foreign banks I would suggest doing research on their regulations. Especially if and how your money is protected in the event the bank goes bust.