"because they deliver sound directly into the ear canal, there's a much greater risk of damaging your ears if the volume gets too loud. ... Earbuds can also push earwax deeper into the ears, causing blockages that affect your hearing, making you raise the volume even more."
Higher volumes can result in hearing damage. There is no magic in it.
You're correct. ANY excessive volume, whether headphones or speakers or natural sound can damage your hearing. Headphones are no worse and no better than any other way of hearing.
I listen to AirPods, closed headphones and speakers. None of them have ever caused an infection. I don't listen for many many hours without stopping for a break though. I don't think any of us do. The batteries won't hold out long enough. This whole "dangerous thing" is silly. It doesn't exist in practice.
There is no problem with volume either. Danger from "delivering sound into the ear canal" is a myth. AirPods do not create much volume at all. They are not dangerous.