There are some things that CAN be done that really shouldn't be done. The big issue with garden hoses specifically isn't that they can rupture your colon because the water flow can be regulated just the same as any other enema. The issue with garden hoses is that most of them contain a carcinogen that can ultimately lead to cancer. …
I agree whole-heartedly that drinking from a garden hose should be avoided despite having done it as a child in the ‘50’s, from a well located on the property with no filtration, along with millions of others.
The the greatest concern should not be of contracting a cancer, but of becoming infected with any number of bacterial, fungal, and/or viral diseases from the critters in the water or become ill from chemicals in the hose material that leach into the water - lead being one of the most notorious.
The issue(s) can be compounded by leaving the hose full of water in the sun, thus raising the temperature of the water. Studies have shown that warmer water increases the amount of chemical leaching as well as an increase in bacteria, viruses, and fungi.
Water pressure should be a concern as well. Water pressures as high as 45 PSI in a home are typical and, when considering the typical automobile tire pressure of 35 PSI that supports a 2,000 pound car, one might see the disadvantages of sticking that garden hose in your mouth or your butt.