But then as you get into it, you realize that you just can't do that if you want to make money.
Take reddit for example. Shaming fat people is legal. Being antisemitic is legal. Being a racist is legal. Most pornography is legal. But it turns out almost no one wants to spend money supporting that. So it makes sense to block things that hurt the bottom line if you are running a business.
To 4chan's credit, they never cared about money, and so they were probably the freest platform out there that somehow didn't devolve into nothing but racist hate, which is usually how absolute free speech social media go (although they certainly have their fair share of it).
Musk was like any other social media outsider looking in -- "Why can't they just allow all legal speech??" And then his pocketbook was on the line and he realized why.