The digestive tract doesn't need to be infected to be effected. AFAIU, in some cases non-infectious viral particles (i.e. non-viable segments floating around in

The digestive tract doesn't need to be infected to be effected. AFAIU, in some cases non-infectious viral particles (i.e. non-viable segments floating around in your body) have evolved to make you cough and sneeze through irritation, so it would be unsurprising if in some people they irritated other tissues or possibly even effected gut flora. If this is in fact the case, then fecal material wouldn't necessarily be a transmission vector. Although it could be; it could be a vector even if the irritation was not by infection.