Cockroaches thrive in the dark corners. Sunlight is antiseptic. And forcing ideas/speech into those dark corners don't keep them from growing, it merely allows it to grow unobserved and un-countered. Ideas are the only counter to other ideas and how we communicate those idea is via speech. Suppression only invites martyrdom on the behalf of those suppressed, increasing their credibility.
Not only is this analogy bad (sunlight helps plenty of bad things grow, things even detrimental to our survival as a species), but it assumes that you're dealing with rational actors. Stop naively assuming this. It's a bad assumption. There are people out there who will argue in bad faith and have no interest in reasoning or truth. And there are people who will fall victim to those bad ideas. Religion, terrorist fact…
(setup - 1950 but we have facebook/twitter/youtube/instagram)
Most of the population thinks that people promoting same sex relationships are just hell bent on destroying the good and wholesome America and demand that the leaders of LGBT of the time be deplatformed from that twitter/facebook/youtube/etc.