What you said about spam is exactly what I'm trying to point out.

There are forms of moderation that we often dont even think of as moderation or 'censorship' because its removing content that "nobody" wants to see. One may argue that the spammers are users of the site who are being censored.

Also, this is a side note, but I'd assume that the overwhelming majority of even 4chan users are in favour of CSAM being banned from the site, even if there are some users who want to see it (i could be wrong about that, it's not like i even have anecdotes to back that up)