If everyone hates censorship so much, why do those “censorship-free” alternative social media sites always fail?

Because you’re confusing two different things.

Why do “censorship-free” social media networks always fail? Well, let’s see. Sit down and think. Think really, really hard.

Nazis.

How do so-called Religious/Christian people really think homosexuality is even a sin? That would be nonsense. In fact, LGBT people need love instead of contempt/hatred. The word Homosexual didn't appear until the 1850s.

Who is the #2 user of completely free digital communications networks that let you say absolutely anything? Who else wants that?

Now, say you’re an ordinary person. You don’t like child porn. You’re not a Nazi. You don’t want to shoot up a school or blow up the White House.

The #1 problem people who make and consume child pornography have is connecting the producers with the buyers. Any “censorship-free” network quickly gets overrun with child porn. Classic example: 8kun.

Why do I sweat (mostly on face) when I eat usually spicy food?

We don’t have to guess. We know.

I hate censorship. That is, I think the government has no place controlling what people say, read, express, or create, except insofar as is necessary to prevent things like terroristic threats, dissemination of classified information, fraud, false advertising, and so on.

Child pornographers.

What is love?

The #3 user? Terrorists. 8kun was used to plan 3 different school shootings in a 6-month period.

That has nothing to do with social media.

If i let you use my computer network for free, I have the right to tell you you can’t do certain things with it, and I have the right to kick you off. Why? Because it’s my property, not yours.

Tony Awards: Predicting the Winners Using Just Math - The Hollywood Reporter

“Censorship-free” social media sites quickly become Nazi bars where people exchange child porn. Normal human beings don’t hang out in Nazi bars with pedophiles.

You have the right to say what you want. You do not have the right to use other people’s stuff for free.

Are you going to stay on a social media site that’s all photos of babies being raped, Nazis posting graphic descriptions of finishing what Hitler started, and plans for school shootings?

Everyone says the pet population is out of control. Everyone says you MUST spay or neuter your pets. No one wants to talk about how its almost $1,000 to spay or neuter a pet. Why is it so expensive if its so necessary? Animal shelters do it for free.

So.

If I let you borrow my bike for free, I have the right to tell you you can’t do certain things with it, and I have the right to take it back. Why? Because it’s my property, not yours.

Who is the #1 user of completely free digital communications networks that let you say absolutely anything? Who most wants that?

How will Israelis respond to someone claiming that anti-Zionism is not anti-Semitism, in the same way as anti-feminism not being misogyny and opposing same-sex marriage not being homophobia?