Which is that it's decreed by a government or similar institution, and that it is enforced by law? That it's about suppressing ideas/material in a whole society?
Whatever privately run sites/newspapers/organizations do, it's other things -- editorial policy, moderation, curation. But by definition it's not censorship. In the same way that having a crappy job isn't slavery, and a serial killer isn't committing genocide. Privately banning certain content on a single site, or newspaper, is editorial policy, end of story.
Words mean things, and a lot of people have fought long and hard against actual censorship, such as the Comstock laws. Let's not cheapen freedom from censorship by turning it into "but I want to say whatever I want anywhere to anyone who wants to listen!", which is what OP is proposing. Freedom from censorship is about having the right to speak -- but it's not, and never has been, about making anyone else give you a platform for it. And this distinction is vitally important.
> Censorship is the suppression of speech, public communication, or other information. This may be done on the basis that such material is considered objectionable, harmful, sensitive, or "inconvenient".[2][3][4] Censorship can be conducted by governments,[5] private institutions and other controlling bodies
I can paste more, but if you just google “define censorship” I don’t think there’s a result on the first page that supports your claim.