I don't think anyone is using the term "diving" as anything more than a euphemism, nor are they perceiving it as anything more.
Let me give some perspective here. Lye, at the concentration used for drain cleaner and stronger is very caustic. It will cause destructive alkaline burns to clothes, skin, and corneas. It will, at the recommended concentration for iron cleaning (1 lb. lye/5 gallons water), also cause discomfort, irritation, and/or damage to tissues it contacts, the degree of which is largely dependent on length of contact. I have roughly calculated that which we use to be about half the recommended drain cleaning strength. So, do I want what's in my lye tank in my eyes? Definitely not. On my clothes? I would prefer not. On my skin? No, not for more than a minute without rinsing it off. If I can't fish a piece out of my tank with coat hanger wire, I have been known to snatch it with a bare hand and immediately dunk it (and my hand) into my rinse barrel without issue. On the one or two occasions I have done so and was not as diligent about thoroughly rinsing my skin post haste, the result was akin to the feeling of a very mild sunburn. After rinsing, the feeling subsided immediately. Will the main website article on lye usage ever recommend barehanded lye tank fishing? No, it still won't.
Lye will dissolve aluminum, or as I have read, lye is a catalyst which allows the water to dissolve the aluminum.