I found the same thing last time I was in the Quetico.  We stopped at a popular campsite 3/4 the way down Quetico Lake that we always use, and there was human shit covered up with pine needles right smack dab in the middle of the campsite (not going to tell you how my brother found it, but we now name that site "poop that shoe"), and a couple bushes around the perimeter of the site had toilet paper and shit next to them.  Never seen such a thing in Quetico in all the years I've been there.  Disgusting and disgraceful.