Why is Garamond italic all wonky?

The angle of the 'upright' strokes in Garamond italic is different between capitals and lowercase.

See, for instance: http://ift.tt/1ARQl3h

This seems bizarre to me. I was reading a book set in Garamond the other day and found this quirk in the italic angle really distracting! Yet Garamond is a hugely popular font, so it's unlikely to be an accident.

Why did the designer do it like this?