The linked article from USGS says nothing about semiconductor-grade purity bromine, but only about ordinary bromine that is used in the chemical industry.

Semiconductor-grade purity bromine is orders of magnitude more expensive than ordinary bromine and the vast majority of bromine producers do not make it.

The USGS article provides no evidence that such bromine is made in USA. I would rather expect Japan to be a producer, not USA, because for many semiconductor-grade purity chemical substances there are major producers in Japan.

Korea does not like to depend on imports from Japan, so I would not be surprised if there was a Japanese source of pure bromine but Korea prefers to import it from Israel. If this were true, they could still switch suppliers in case of a shortage.