I have no idea how “big” drug busts on US bases need to be to be news worthy but the details of this bust seem underwhelming:
Joint raids by South Korean police and the US Army's Criminal Investigation Division found 77g (2.7oz) of synthetic cannabis, more than 4kg of "mixed liquids" used for vaping and a total of $12,850 (£10,440) in cash at the 22 suspects' homes.
Some were arrested by South Korean police, so they will likely face trials by South Korean courts. If we break laws in foreign countries, we're still subject to punishment under them. Service members can and frequently are also held to account under the UCMJ and will likely have court martial as well. Have seen plenty of people get arrested for myriad crimes, and then get slapped with an NJP/court martial on top of it.