As explained in the article, the Korean companies did not come to USA due to their own free will, but because they had been blackmailed by the US government to invest billions in USA.
However, after making the forced deals, USA has not provided the work visas that are needed for the completion of those projects in time, compelling the Korean companies to use visas of an incorrect kind.
I see here only trust broken by the Americans, not by the Koreans. In recent years, everybody all over the world has learned with dismay that any deal made with USA is more or less worthless, because USA may not comply with it or change its terms at any time.