Wait what? They added a system to filter traffic, to avoid having the government make it mandatory to have a system for filtering traffic? That seems silly.
There are also PR reasons. The general public unfortunately believes that this is a good thing and is indeed "protecting" children. IMO it would've happened regardless of regulatory reasons.
This happens with regulations all the time. For example Apple allowing sideloading of apps on their phones in their own terms before the European regulators tell them how to do it