If my friend on Facebook tags me in a photo, I can untag myself. If someone posts something on my wall, I can delete it. This is already a feature. If they opt me into having my picture featured in their ads I can opt out. They already provide methods for censorship, you can remove or undo things other people do. So if Facebook auto-tags me in a photo, I can manually go through and untag myself. Since I already have the option to do it manually, how is it worse to allow me to opt out all together, or let me automatically do it?
See I don't think the problem is that I don't know what censorship is (I do know what it is, thanks for the explanation*), I think the problem is you don't know the already existing functions within Facebook (like untagging photos, or deleting other people's wall posts).
* When you delete something you wrote out of concern someone may find it and use it against you, this is self-censorship.