Suppose there is a shared server outside your jurisdiction which is hosting a wide variety of content none of which is a violation of the law in their jurisdiction, but 2% of the content is a violation of the law in your jurisdiction. Or isn't hosting any content at all but also isn't a jurisdiction that does the same censorship as yours and then people can use the connection as a VPN.

If people in your jurisdiction can make a secure connection to it, e.g. to get the 98% of the content they have which is lawful in your jurisdiction, then they can also get the content you were trying to ban because you can't tell which one they're doing. Preventing this is all or nothing: Either they can connect to the server that isn't subject to your laws, or they can't. And the latter is heinous and tyrannical.