An online vendor has become embroiled in legal action for selling T-shirts featuring a smiling image of North Korean leader Kim Jong-un, in a case highlighting the polarized perspectives of South Koreans towards their northern neighbor.

Six right-wing activist groups have filed a joint civil lawsuit against two individual sellers, with e-commerce giants Naver and Coupang also named as defendants for displaying the product on their platforms. According to the complaint submitted to the Seoul Metropolitan Police Agency, the involved parties allegedly violated Article 7 of the National Security Law, which prohibits actions that "praise, incite or propagate activities of an anti-government organization," or the distribution and sale of such materials.

“The parties accused have done more than just paint a friendly image of Kim Jong-un; they knowingly threatened South Korea’s liberal democracy by praising and inciting the North Korean leader in clear violation of the National Security Law," the plaintiffs claimed in the filing.

The now-deleted product listing showed the T-shirt priced at 14,900 Won ($11.50), available in various colors. Below the North Korean leader's smiling face printed on the front, the T-shirt bore a caption in North Korean dialect wishing good luck. Its 4.9-star rating based on 69 reviews indicated its allure to shoppers who have a taste for outlandish designs.

Despite the controversy, there is no evidence linking the T-shirt's designers or sellers to North Korean affiliations, let alone a political agenda. Hashtags associated with the product, such as "funny," "parody" and "useless gift," suggest its intent was humorous.

South Korea's National Security Law, established in 1948 to counter the looming threat from North Korea, forbids any positive commentary or dissemination of North Korean propaganda, with violators risking up to seven years behind bars.

Leading global human rights organizations, including Amnesty International and Human Rights Watch, have argued that the law infringes upon the basic freedoms of speech and assembly. Ambiguous phrases within its provisions like "praising" and "anti-government organization" are seen as potentially suppressing democratic dissent -- recalling South Korea's history from the law's creation until the 1980s, when the law served as a potent instrument for the country's series of authoritarian dictatorships.

The law has faced multiple challenges in the past, but the Constitutional Court has upheld its constitutionality in seven separate instances since 1991.