Before I started nursing school I worked in a nursing home. I had a patient with an ostomy, but she was allergic to the adhesive from the bags, so they simply secured it with a couple of 4x4 gauze and lots of tape. I had to be VERY vigilant about her ostomy care because there was nowhere for the feces to go except out the sides of the taped gauze!
After dealing with that for a year, I don't mind colostomies at all because everything is secured in its little baggy.
And as the others said, as you get more used to dealing with these things, they should bother you less and less. I am honestly more grossed out by baby BM because at least in newborns, it's a weird color/consistency (I don't have kids). At least with adults it generally looks "normal".