The counterpart "safe" TLD is part of a much bigger content curation problem that is evolving in the Internet. Some parents out there are not at all OK with Disney content, even, some will want to leave boobs in but head-crushing out, etc, etc. Properly tailoring to people's many shades of content filtering seems like a job for dedicated browser-recognized crypto certificate chains.
This way, different consumers can directly delegate trust to a custom choice of entities that already are engaged in this space (e.g. all the "family focus" agencies), instead of fighting over a centralized TLD committee.