To all the people putting guys down for using it, screw you. If it gets dad's more involved in parenting, that's categorically a good thing!
Is it a cheap trick to boost some men's confidence? Yes. But so what? If your wife has an overly girly nappy bag, an "ironic" overly manly one has a lot more effect than you might think.
A lot of men are very insecure, when it comes to parenting. There is a massive amount of training and advice out there for mums, but VERY little for dads. We are left in a limbo of either being disconnected, and complained about, or bumbling and being complained about. It's improving, but slowly.