Technical measures while technically existing failed first in China and then in Russia lately, Russian authorities recently all but admitted that they can not block xray+reality-style VPNs (which were and are developed in China to go over their "great firewall") and now talk about a blanket ban on foreign traffic and basically a whitelist for internet.

The goal is always a perception of control of public narrative. Those people deeply care what "masses" think of them. That they measure mostly by sampling more or less public media (and I actually worked at a company in 2010s which was selling exactly that). And when they don't like what they see, they try to fix that by controlling that media, up to and including banning the whole world.

That is what is happening with all this protecting the children stuff.