Whenever we achieve the grand unified theory of comment sections, it will include a formalized concept for this process of context loss as an explanation for where arguments come from.

The deeper in you go, the more likely that the reason the point was raised will be lost. And crosstalk will arise between people carrying on the original point and those who experience the latest comment as its own starting point.

Fact is the issue was largely already solved, even though the perception was that the water was still unsafe.