I'll just use one of the many other services that does it for me.
"it's too hard"
which translated of course means, "the cost benefit analysis doesn't come down in favor of spending the effort".
Caveat emptor, informed consumer, personal responsibility, blah blah blah.
What the Freedom Markets™ advocates don't acknowledge is transaction costs. If consumers have to vet every single activity, the economy suffers.
If YouTube Kids is marketing themselves as kid friendly, it'd be nice if it was true. My skepticism budget is finite.
Forcing YTKids to only show PBS Kids content on every platform is a huge pain in the butt.
I'm just going to assume you are being sarcastic and making an ironic point about parents wanting to control what their child sees but then not putting any personal effort into it.
The harsh reality is that parents have to do work. I remember when I was a kid I hated that my parents looked through the books I checked out from the library to see if they were "appropriate" and that sometimes they would remove horror novels and other things that they thought were not age appropriate.
But the truth is at least they cared enough to check and at least they were consistent, and later on when I became a teenager they gave me more freedom. If you have opinions about what media your child has access to you have to do the work to curate...
Of course I want to review the content too, which is why I usually watch new stuff with them. But I want the service to take the first go at it. Like every other streaming service for kids.
Same thing at the library. When I get a book from the kids section, I can be reasonably sure that I won't be surprised by some adult content when I sit down and we read the book together.