I think the idea of the law is that now they would be required to block those lists.

Correct. In any case, I would not trust the government and courts of any country with such a huge loophole ("anything that might become banned in the future"), let along those of Russia.

The biggest problem with those lists is that any courthouse from a tiny town in a middle of nowhere has the power to add resource to the federal list. People who do not understand what they are doing. Thus we have seen the whole lib.ru being added there at some point, along with some parts of Quran declared extremist materials.

And now they want some random NGO to be compiling their own list of paedophile resources. They'll have all the control without much responsibility, hurray.