This was given as an example of something that looks more inhumane in pictures than it really is. The reason it looks inhumane is because one imagines the sow would prefer freedom of movement, as other living things do. The reason why it is done is certainly relevant, as is how long they are kept in that position, whether they ever appear to be in distress trying to move about, etc.

None of this is visible in a photo, and needs to be explained. However, I don't buy the argument that people have no right to see where their food comes from because they just wouldn't understand what they're seeing. A system where living things are raised for our benefit seems like a place where more transparency is called for, not less.