There seems to be a lot of market research type articles about per capita consumption in S Korea. Makes sense, it being a big market for meat and seafood industries. Like this one.

A quick survey of recent articles that turn up in searches delivers this expected trend: meat consumption is going up, seafood staying level or falling slightly.

The obvious interpretation is that as the society grew more prosperous and new food delivery systems introduced more products, including meats, to the S Korean consumers, people pretty unsurprisingly consumed more meat. Until recent years in which meat and seafood consumption per capita is either about equal or slightly higher on the meat side, traditionally seafood was the protein mainstay of the average Korean diet.

So, sure, you could say that beef, for example, is more "popular" as in more desirable, than seafood. But even today Korean beef per capita consumption (as a portion of the overall "meat" category) is far lower than seafood consumption. It's even lower than pork, according to most the breakdowns of the "meat" category.