Knowing that that's what the kids are watching, why are you still allowing them to have access to YouTube?
If that specific video exists and if it's common, this conversation could be had; but, it's relatively uncommon, making it a surprise.
The real answer, as someone else has alluded to, is that YouTube is something that parents should watch or be aware of with their children.
There is a great deal of valuable information on YouTube and cancelling it wholesale is absolutely the wrong approach.
It is common: https://en.wikipedia.org/wiki/Elsagate
Youtube is not something kids can use without supervision.