This discussion is absurd. If an institution wanted to filter Wikipedia, they could copy it en masse and just leave out the naughty bits. I don't think the license could forbid that.

The fact of the matter is that censorship is not trivial. The cost of filtering should be burdened by the censors, not the Wikimedia Foundation itself.

Edit: Jim Greer points out that Wikipedia actually does suggest using proxies for censorship, http://en.wikipedia.org/wiki/Wikipedia:Options_to_not_see_an...