That's strange. I usually hear this expressed by people who have personally had their views censored out of the public sphere by some authority who was actively marketing the opposite view.
I usually hear what you've expressed from people who are glad that other people were censored: a vague argument for the existence of the possibility of censorship that isn't meant as political suppression, one which usually relies on accusing any possibly censored hypothetical person of likely being crazy, stupid, or a foreign spy.
Rather than an argument, it's an encouragement to use those priors when calculating the odds of the next "conspiracy theory" being censored off the internet actually being true. Remember, arrested people are usually guilty, because most of the guilty people I know about were arrested...
I have to add that I hear this premise expressed quite often from people peddling low-evidence medical advice and not-quite-believable conspiracy, who try to give credence to their theory by pointing out that the people-you-don't-like disagree with them, no matter what the grounds of disagreement actually are. (I've seen people refer to this thought pattern as the "Galileo fallacy", although we also shouldn't let these named fallacies turn us away from actual interesting ideas just because the public disagrees, too. It's a balance.)