Censorship implies people have the right to say what they want and are being restricted somehow. In the context of your hub, they do not have that right.
Consider your Hub like a piece of property. A hardware store is a piece of property too. If you owned a hardware store would people have the right to post anything they wanted on your front window? Maybe a competitors advertisement, or maybe just graffiti? Probably not, and in the same way you shouldn't let people post whatever they want in your Hub comments. Respectful debate is fine, but unfortunately some people aren't so "restrained".
Also, if you have an Adsense account you are responsible for all content on your page, including comments. You don't want some clown posting a nasty spam link or some other nonsense that may endanger your account, right?
The ability to deny comments on Hubs is a good feature. It's always smart to have your comments set for moderation before they appear on your Hub, and weed out anything that is detrimental.