It seems like you have not understood the argument. It’s very simple: If you leave the water bath so it cools in the room, it will get a bacteria growth. What kind of bacteria is difficult to say, unless you have laboratory in your home. If you warm the water again to the sous vide range, the bacteria most likely will die, after some time in that temperature. But the foul taste will be there caused by dead bacteria and the toxins they have produced. If a pouch punctures, it will suck in water and hence get a pinch of foul taste. This is not advanced science, it’s pure logic and has happened numerous time.
This matter is very simple: if you cannot drink it, don’t use it. Fresh water each time. I have been in the food business too long to take any risks regarding cleanliness.
If you keep the water warm between the uses, bacteria will not develop. But if your argument for reusing the water is environmental, I am sure you appreciate that the energy you use for keeping the water warm is pure waste. But the water can be used for watering plants etc. That’s what most of the water in California is used for anyway.