Just for fun, let's have another go at answering the question in the OP -- is circumcision without consent wrong.
Think of it this way -- somebody waylays you on the way home from enjoying a Big Mac, tosses you into the back of a van, ties you down and whacks a bit off of your willy! Is there any question left? Is it wrong?
Well the arguments presented have not convinced me there is any moral justification.
That it helps prevent certain diseases fails, because one could argue that amputating the toes of a child prevents gangrene from an ingrowing toenail. The simple fact is that we can easily prevent such diseases and infections now, without an unnecessary mutilation of a child's genitals.
The argument it would prevent certain std's fails as well, since an adult can have the procedure and give informed consent, and of course unlike the biblical era a condom can also help prevent many of these.
The argument it is harder to perform on an adult fails, since an adult would not be obliged to have the procedure, but can of course give informed consent, which a child cannot.
The funniest and least compelling argument, was the idea of retrospective consent, paraphrased as an adult saying they grew up and were happy to give consent to the procedure now, which of course defeats the idea it needed to be forced onto an child that can't give informed consent, as that adult has shown they would still want the procedure when they have grown up, and are able to give informed consent.
So no, I see no moral justification in any of the arguments presented.