Take some of those same bacteria and set them directly against the intestinal lining without any of the delicious mucus in the way and you’ll have a slightly unpleasant time. And I’m being literal. It’ll be aggravating, and deleterious to your long term health, but usually not immediately life threatening. They’re absolutely beneficial, but they’re in it for themselves. They’re not beneficent, they just are, which was all the point I intended to make.