This. My 7 year old watches some awesome Lego building channels and some gamers that I've checked to be OK.

For at least 6 months we have forbidden our 3 year old to watch YouTube because he ended up at some (harmless, but totally braindead) Spiderman nursery rhyme video and I figured he would be caught by bad algorithms.

Sometimes the 7 year old wants to be nice to his brother and searches for spiderman. He knows they shouldn't watch violent stuff, but it feels like a drug somehow to watch autogenerated content at all.