This is reason #597 why you just don’t allow platforms to censor.
If a site wants to be a publisher, by all means, be a publisher, and don’t monetize user content.
If a site wants other people to provide the content for free, then sorry- no censorship for you.
“Community guidelines” etc are just censorship with a nicer name.
“The algorithm” is just opaque censorship by making content undiscoverable. “un-content” in Orwell speak.
There are valid use cases for on-topic/off-topic. User content sites should have to declare whether they are a single-topic community or not, and act in good faith either way. If you are a single topic site then you must aggressively prune everything that is off topic (not just some off-topic). If you are multi-topic then no censorship for you.
And multi-topic sites like Reddit have to do so per channel/subreddit/etc. but the key points are “on/off topic” is the only valid filter criteria, and it must be applied consistently and in good faith.
If your algorithm is the secret sauce that makes your platform worthwhile/profitable/whatever, then people must be able to opt out, eg opt into a “only stuff I follow, all of it, most recent first”.
Or if you care about your users then implement curated feeds, allow users to create their own curated feeds, and implement your algorithm as the first curated feed.