I mean, there are politicians in democratic states who believe that protections afforded to the press on the basis of rights don’t apply to, for example bloggers. It’s not altogether obvious why freedom of expression or speech should automatically include the internet.
The primary diplomatic function of the U.N. is laying down specific guidelines for international conduct, so that there's no more arguing about what constitutes a violation of a specific treaty.
For example, suppose Ukrageria says, "But Zimbraqistan stationed 14 battleships outside of our port, that's an act of war," and Zimbraqistan counters, "But we just want them to lift the 200% tariff on Zimbraqistanian goods." The U.N. has specifically said that free access to ports is a sovereign right, so that resolves this dispute and gives Ukrageria international support for a declaration of war against Zimbraqistan.
Similarly, some countries have criticized Egypt for disconnecting its citizens from the global internet. Egypt in turn counters that their citizens still can express their opinions and speak freely so it's not a human rights violation. The purpose of the U.N.'s resolution is to resolve this dispute and clarify that freedom of expression must include international communication over the internet.