Imagine if you submitted a letter to the editor to a newspaper and got back a response saying they were refusing to print it because it violates their rules for appropriate content.
Now imagine you storm into the lobby of the newspapers' office accusing them of censorship and demanding that they print your letter. They'd call the police to please remove the crazy person. Nobody would have argued that you are entitled to having a letter published in someone else's newspaper. That's clearly insane.
Freedom of speech doesn't mean you are entitled to use someone else's property as a platform. The vast majority of the complaints about "free speech" I see today are people who seem to believe this. It's like we've become so accustomed to free (ad supported) social media that we've started to think it's some kind of entitlement.
There are very few things you can say (in the US) that will get you actually censored. I can think of copyright infringement, explicit threats of violence (and the bar there is very high), or child pornography. Other than those you can pretty much say anything you please. I am not aware of any time in the history of civilization when speech has been this free.
Edit: I must point out that my comment is US-centric. There are quite a few places in the world that don't take free speech as seriously. But I don't get the impression that's what this petition is about. It's about "cancel culture" which means "people refusing to let me use their property for free to promote any message I want."