Perhaps for the same reason the US extended its trade embargo with Cuba to include foreign companies trading with Cuba - https://en.wikipedia.org/wiki/Helms%E2%80%93Burton_Act

Or for the reasons that people have divested from companies doing business with South Africa under apartheid, or the Boycott, Divestment and Sanctions Movement regarding Israel, or any of a number of other examples.

See also https://en.wikipedia.org/wiki/Solidarity_action .