Semantics can be used to trick people. But it doesn't work on an old trickster. America didn't "impose" democracy on SK. It provided the ingredients necessary for democracy to be born. Without those conditions of "domination" democracy would not have been born in SK.
First, the ROK/USA mutual security treaty created the political and physical space for SK to exist.
Second, America's open market allowed SK, like Japan, to evolve an export driven economy that lifted the living standards of the people of the ROK.
Third, the US restrained the South Korean military dictatorship. Not with respect to the Kwanju Uprising and Massacre, but in 1987 the Reagan administration restrained the dictatorship from repeating the Kwangju massacre. Without the ability to quell the demonstations with brute force, the dictatorship was replaced by Roh Tae Woo who paved the way for democracy.
Take America out of the equation and there would be no democracy in South Korea. I remember the SK movement for democracy came to a head not long after the inception of People Power in the Philippines. One cannot honestly ignore the context and milieu established by Pax Americana.
South Korea had no history of democracy. The idea of democracy has not originated independently in any non-Western polity in history. Ever.
Edit:
http://www.tfd.org.tw/docs/dj0301_new/099-126-Sangmook Lee.pdf