YouTube has too much information to just ignore for education. It's the most efficient method of learning for many topics and for many people.
It's closer to PBS than a porn site imo. (The idea of a porn site with YouTube's puritan guidelines sounds pretty funny.)
You can get literal pbs at pbs.org for $5/month, or your local library for free.
On the other hand, porn services are (generally) actively blocked in educational institutions, so the content, regardless of its educational quality will never be suggested to kids because they are not a target audience. (Not to mention the legal trouble these services would have from actively enticing minors) I doubt we’ll see “PornHub for kids” our RedTube signing a contract with Blippi or Miss Rachel.
It could be that someone happened to post educational videos to the porn site. If so you'd might as well download them while you have the chance, but don't mistake their existence for some indication that that's what the site is for. They're still less than 0.1% of the videos, and you'd need to specifically search for them or be linked to them to find them. Assume you'll need to look elsewhere for educational material. e.g. there are 10s of thousands of results for videos for "Holocaust" on worldcat.