Yeah dogs react um differently to smells than we do. In particular, BO and poop smell doesn't seem to bother them. A lot of dogs sniff poo. Some eat it, which is a disorder, but it shows you how much they do not avoid it.

My theory is that since they're so sensitive it doesn't make sense for their smell sense to be offended by a smell that frankly we probably carry around to some degree all the time. At the same time dogs instinctively poo away from home.