I see this all the time as a defense. It is actually the preferred defense of Mac fanboys and tech apologists of all stripes, and it's pathetic.
Yes, Foxconn makes things for many different companies. Yes, conditions are terrible across the entire Special Economic Zone. But it is bizarre tech fannishness in the extreme to somehow think that because others are implicated in a crime that this somehow absolves Apple. It's like a child being caught with their hand in a cookie jar pointing at other children and saying, "They did it too!"