YouTube like many things is an amazing tool when properly used.

My rule for my children is the same as most tools:

Until you understand its danger, you dont get to use the tool freely.

Letting my kid have access to something as dangerous as perfectly-crafted-digital-addiction-in-a-glittery-rectangle is about as sane as handing a toddler a meat cleaver.

All that to say, I agree. YouTube, as is used by the masses, is likely causing serious mental deficits to a level we probably cant understand yet