OT: Do you think medical science is valid, or do you consult YouTube for medical advice?

I think it's more a matter of the algorithms Youtube have rather than the content.

Youtube has informative and useful videos about just about everything, but the videos aren't that popular and youtubes algorithm causes the videos about a similar topic that are most popular to come up far more often than anything else.

For example I searched for a video explaining why my cousins dog was showing hostility towards her 5 year old daughter (nothing serious, just growling). Turns out it's because the child was growing larger than the dog which causes the dog to think his position in the pack was threatened. And because the kid didn't understand you shouldn't stare a dog in the eye or pat him on the top of his head (both which a dog sees as challenges).

But the next thing I know the recommended videos are flooded with fluff about dogs reacting to (and protecting) babies for the next week. Adorable videos, but it gets old fast.

If you want informative videos, you need to search for them. And like googling, it's a skill.