SEOUL, South Korea — A government critic who called the president a curse word on his Twitter account found it blocked. An activist whose Twitter posting likened officials to pirates for approving a controversial naval base was accused by the navy of criminal defamation. And a judge who wrote that the president (“His Highness”) was out to “screw” Internet users who challenged his authority was fired in what was widely seen as retaliation.

Such a crackdown on Internet freedom would be notable, but perhaps not surprising, in China, with its army of vigilant online censors. But the avid policing of social media in these cases took place in South Korea, a thriving democracy and one of the world’s most wired societies.

The seeming disconnect is at least partly rooted in South Korea’s struggle to manage the contradictions in eagerly embracing the Web as one way to catch up with the world’s top economies, while clinging to a patriarchal and somewhat puritanical past. In a nation so threatened by Lady Gaga that it barred fans under age 18 from attending a concert, the thought of unlimited opportunities for Internet users to swear in “public,” view illegal pornography and challenge authority has proved profoundly unsettling.

“Not so long ago, the role of the government and the role of the establishment, including the press, was sort of the benevolent parent of the masses,” said Michael Breen, author of “The Koreans: Who They Are, What They Want, Where Their Future Lies.” “The government always knew best and the people were kind of stupid. I think still a bit of that is lingering on.”