White vinegar kills weeds and most microbes due to its high acidity. If you remember from biology class, most bacterica do not like to live in a Ph level of 3. This is not some random information. It is been researched and documented.
As for being anti-microbial. The soap you use in the morning with a high Ph is anti-microbial. That is why you use it. Evaporation, UV rays as well as bleach and ethenal all kill bacteria, yeast and molds. Many things destroy microbes. Some of these are harmful to humans and other animals, while others are not.
Vinegar kills weeds also because of its acidity. Salt and dry condititions doo too. I do not recommend drinking vinegar straight or eating a large quantity of salt. In moderate amounts we do eat these products without harm.
Remember, as animals, we are far more complex then plants or bacteria. We have developed ways to efficently remove toxins from our systems. Also, we are much larger and a small amount of vinegar will not hurt us (or a chicken) but will hurt a plant.
DB