It's probably just politics, I think the US might find it more difficult to threaten to sanction South Korea. Or it might not. But definitely SK has a bigger position of strength relative to the US than Taiwan or even the Netherlands.
Samsung is nearly 40% of the SK economy. An attempt to put sanctions on it would SEVERELY cripple their economy. And I would expect a backroom deal before they want that blow.
According to wikipedia Samsung's revenue is around 17% of SK's GDP. Still a huge amount, but considerably less than 40%.