Trying to understand what you're saying -- I believe when you say "their preferences" you mean that people want "basic as-pure-as-possible H2O that they paid for". However, all water that we drink is purified by a wealth of processes. That's not pseudoscientific, that's real science. Our purification is the reason we don't get cholera, for example.
If you mean that people want non-pink water, I think that's reasonable. But I also think it's reasonable that the reason the pink color is explained by the actual purifying process. I too concede that the water controlling authorities screwed up by using too much of the chemical, but it seems not in a dangerous amount, and they did well to communicate exactly why, and they also conducted tests to ensure safety of the water, thus effectively following up and checking the potential problems with their screw-up.
As far as government mistakes go, I think this one was relatively mild and handled in an adequate manner.