Luckily, we're collectively beginning to grow past the naïve belief that free speech is a virtue in itself, an ends, and understand it properly as a means, a tool, which we're all obliged to use ethically and responsibly to make our society better.
You are free to not use reddit, or create your own reddit.
There's plenty of material in the philosophical world about freedom of speech in regards to censorship by private parties and other people.
There is no real argument that a company like Reddit must adhere to free speech. No one forces you to use facebook, reddit, or any other website.
I think most people's idea of free speech doesn't align with what you are saying.
Obviously you should be allowed to boot people from your house for being an asshole. And many businesses should probably also have the same right.
But there's also the ambiguities that mean it should be as simple as 'private property overrides everything else'. Some companies are utilities, and can't dictate whether someone can use their service based on personal views (electricity companies, water companies, telephone networks, etc). Sometimes someone's role means they can't be that selective about what they hear, like how a judge found it was unconstitutional for Trump to block people on Twitter. And there are issues about either public vs private property (like for company towns) or instances where a company is so large and has such a huge share of the market (like a monopoly) that you could argue whether they should be able to pick and choose what they like.
It does not mean "I can say what I want and you have to leave me do it".
Free speech is a tool, like democracy and discussion and rhetoric and liberty and communalism and a thousand other things besides, which we should judiciously and precisely in order to make our society better.
Or do you mean to say that isn't censorship?
Free speech is an amoral tool, which can be used to improve or degrade the human condition, when wielded appropriately. It's our job to decide when and how to use it, and not act naïvely and pretend it's a virtue in itself.
Soviet censorship vectors were able to wrap dissenting viewpoints as "counter-revolutionary" or "bourgeois" without regard for the consistency of content to the wrapper.
In the US, most people have always had an understanding that speech should be used responsibly. The early Internet was overstocked with utopian idealists, me included, who thought this new age of instant communication meant that good ideas would quickly triumph over bad. That led to a lot of naive policies.
In practice, that didn't work. We hoped for a great age of dialog and understanding. Instead, we got an era of "don't read the comments", because it turns out the small number awful people are perfectly willing to spew awful talk all day long driving out the reasonable people who have better things to do. Now anybody running a significant platform knows they need to deal with abusers and monsters or they'll end up a cesspool.
The same utopian thinking has often gone with new technologies. Standage's "The Victorian Internet" makes clear that the telegraph was seen with the same rose-colored glasses. It was going to end war! To knit humanity together into a great brotherhood! Spoiler alert: it didn't.