You replied to a comment where their primary concern is, quote: "When a scary clown jumps out and screams, that's traumatizing". Not porn, sexual innuendo, or pedophiles looking for potential victims. Not war, or violence, or even brainwashing advertisements. It's clowns... their primary fear about YouTube's content is the possibility their sensitive child will be exposed to a clown.
It's impossible to satisfy everyone, regardless of the content rules, and no mater how curated. YouTube could spend a billion dollars curating content, along with surveys where 90% of parents have to approve a video before it is included, and the remaining 10% would still be the vocal minority ruining it for everyone.
Sure, YouTube probably doesn't do quite enough. But when you have parents looking to let YouTube babysit their 2-8 year old children without supervision, whose fault is that? YouTube's, I'm sure. /s