There can be legitimate concerns by governments as to some areas of items one can access on the Internet where government censorship can be justified.
Child porn and nude or semi nude pictures are taken without the person's permission is illegal in many jurisdictions.
Military secrets. For example I saw a news item where allegedly a Google map picture showed an advanced and secret drone aircraft at Lockheed's 'skunk works' facility. I suspect the US Government demanded that such picture or of any such secure areas be unavailable.
There could be Secret Service as well as 'homeland security' information (like information of critical infrastructure, security procedures) that should not be public information as could be used by terrorists and criminals.
Information on criminal investigations, of people involved undercover, where it could destroy them letting alleged criminals go free.
Proprietary private information that if taken and used can ruin a company.
Personal information that allows identity theft or critical personal information that can be misused and run your life. Pictures in the streets (Google views) with potential invasions of personal privacy
Sites with stolen copyright, trademarked and otherwise legaly protected materials allowing downloaning without the compensation of their owner.
Where the conflict kicks in is for example with 'Wikileaks' where much of the information is embarrassing or discloses immoral policies like with torture, political repression, or withholding of criminal behaviors by governments.