Yes, I am well aware of the horrific dangers of dysentery and other diseases which present with diarrhea as a primary or secondary symptom. I was commenting on the poster's ignorance of the fact that diarrhea is a symptom and not a disease in and of itself. It's basic medicine that you alleviate the symptoms when you can, but treat the disease. Now in cases like cholera and the rotovirus, when the symptom can kill all by itself, it is utterly essential to alleviate that symptom, but you still treat the disease as the primary cause.
You can't just give someone a "diarrhea vaccine." It's a potentially deadly symptom with thousands of possible causes. That's one of the reasons the preferred method of treatment in so many parts of the world is oral re-hydration. They are not trying to cure the cause because they probably don't know what it is, so their primary goal is to simply enable the victim to survive the symptom, cross their fingers, and hope for the best.
Rotovirus and cholera vaccines are damn near essential in some parts of the world, and it's assholes like this that are helping to make sure those who need them desperately do not get them by calling into question their very existence.