I don’t think a wedding registry is a “ traditi[o]n that stems from the sexist and dumb notion of a dowry”. I don’t see how a wish-list for gifts is, in any way, sexist. It might be that way if only friends/family of the bride were expected to purchase, but it’s not that way at all.

I think you are over-thinking things… it’s just a wish-list, little different from a birthday or Christmas list. And buying something (on the registry or off) is no different from any other gift-giving occasion. And you don’t HAVE to buy off the registry; you can certainly give the item of your choice, or cash, or nothing.

(That said, I question the sanity of somebody that is putting a replacement Brita filter or a pizza roller on their wedding registry… WTF? Just ask for cash for the honeymoon if you run out of ideas.)