Its a mix.
Some of them think its safe, others think the risk is overblown, and a lot just don't want to deal with their kid having a shit fit.
In the UK, unless you are adopting a kid with needs, you will not get any parenting training. so you're on your own on how to deal with children. TV was safe when I was a kid, and younger parents who grew up with digital TV also had safe watching, why would youtube kids be any different?
With my kids (and yes this is a boast, I'm middle class, this is how we assert dominance) I was lucky enough to be able to enforce time limits of TV/netflix etc. They also aren't allowed youtube on their own, so never got onto the conversion ladder from crap to exploitative crap.
crucially they don't have tablets/phones whilst bored. TV is a treat, so boredom requires them to sit there and fucking day dream like the rest of us.
Parental training has not been the norm in most societies and most times. The problem in the modern west is that people lack the community and family support that helps parents. This combined with other things (lack of time with two parents working full time out of the house being usual, parental addiction to devices, etc).
> TV was safe when I was a kid,
Safe in some ways, but still harmful. it was passive and a substitute for things that helped you develop. A lot of parents (mine included) limited TV for just this reason.
> TV is a treat, so boredom requires them to sit there and fucking day dream like the rest of us.
Exactly this - one of the things I had in mind with regard to TV being harmful. Even in the days when we had three or four broadcast channels and that was it!
> I'm middle class
Worth noting that the British and American definitions of middle class are quite different.