I think the word you were looking for was "libertine".
Definitely not the same thing as "libertarian".
Libertarians (the right wing kind, at least) pretty commonly get made fun of/characterized as pedophiles among other things so they probably did mean libertarian lol
This comment has been downvoted but the phrase, "What if the child consents?" Is actually bandied about frequently on political subreddits like r/libertarian as a mockery by their detractors