I agree that older men preying on younger women (and girls) happens a lot, and is disgusting because of the power and economic dynamics, exploitation and misogyny, not to mention the deleterious effects you mention on the victims. It is also disgusting because if society is disgusted by older women having consensual sexual relations with younger men, well what’s good for the goose is good for the gander. I understand your rage.
However, I still fail to understand why asking for proof of age is itself disgusting to you, apart from the associations. Yes, women should also be symmetrically asking for proof of age from their sexual partners of any gender, so the woman Joe Duncan carded should have responded with, “That’s a great idea! I’ll show you mine and you show me yours.”, no matter the seeming age of the potential partner.
The real issue also is how do we prevent family and culture from destroying the self-esteem of young women so that they can see through the typical loser predatory older man and don’t want to associate with them.