This is a confusion of Censorship vs quality control. Not putting knitting in a fishing magazine doesn't make knitting content completely unavailable, you just have to look at the knitting magazine. This is the marketing strategy of private enterprise.
Censorship is generally referring to government control over what people have the legal ability to view. If a private enterprise had a monopoly on knitting and then hid it, that could be seen as censorship I suppose.
The idea of censorship being bad plagues my every day life, given that I live in a country controlled by an authoritarian regime where you can go to prison simply for the intention of handing out stickers promoting women's rights on women's day.
The reason it's bad is because a small group of powerful people get to dictate what is right and wrong by promoting what pleases them and censoring what doesn't.
Anyway, as pointed out below, this is seemingly totally unrelated to this OP so better leave it at that!