We've spent most of the 20th century honing propaganda techniques to the point where its potency is like a nuke compared to a dynamite stick. And then we've spent most of the 21st century so far making that nuke cheap and easily available to everyone.
I'm very pro-free-speech in general and I don't think censorship is a solution, but in order to argue for free speech in good faith we have to acknowledge the problem. The reason why people want government to censor is, in many cases, the same reason why they want government to crack down on someone who is building a nuke in their garage (but are okay with the government itself having the same nuke).
I don't want everyone building nukes in their garage because nukes kill people en masse in an instant, and I cannot counteract the effects of someone else's nuke by setting off my own nuke.
People want the government to do their work for them. But you can't expect someone else to advocate for your interests automatically. The only relationship where that happens reliably on a regular basis is that of a baby and a mother. The government is not your mother. The government's policies are the result of the intellectual output of its citizens in a democratic society. You are supposed to control it as a citizen, to serve the interest of yourself and other citizens. It is not an entity that you can delegate decision making to and expect no consequences down the line.
If you think someone else's ideas are wrong, put forward your own. I don't think we should ban propaganda, as that would require a central authority to determine what info is/isn't propaganda and thereby creating propaganda in the process. I think we should ban the mechanisms that encourage the formation and snowballing of intellectually/ideologically homogenous groups on the Internet, thereby making it a hostile environment for propaganda and similar heuristics in general, so that the best ideas may thrive in dynamic competition.