Anti-laundreing is the main reason. Serbia? They forgot to add Russia too
I've heard nothing about that anywhere else but in that article. It's probably someone from localbitcoin doing some major dodgy activity.
p.s. knowing how many times people confuse Serbia with Syria and Siberia, that just might be the case.
Just as I've thought:
Checking on the link kwabeedat provided, They've meant Syria not Serbia.
There is original Press Release translated to english, and you can see that Serbia and Syria are both on the list, can it be bad translate?
This is the key message to lick the US government and its blind allies in order to avoid future problems.
The main reason behind this isn't explicit yet and these countries don't have a considerable weight in the crypto-world. I think that this exchange will try in the future to expand its activity further.
It is true that South Korea and USA are great allies, so it is possible that some countries from Bithumb block list may have connection with USA travel ban list which include : Iran, Libya, Somalia, Syria, Yemen and North Korea.