Yeah no doubt, it can be absolutely dangerous. But hydrochloric acid will absolutely destroy you, but can be completely neutralized with a 1:1 ratio of water.

After leaving the treatment plant it would be introduced to a million gallons of water.

What concentration would that have been when it reached the faucet? Hard to tell, im sure someone can figure it out. They increased the concentration 100x at the facility. But there are several more steps to the treatment before even leaving the facility.

Im not downplaying the possibility of how dangerous it is, but the concentration at the faucet would likely have been nothing more than a mild irritant.

For example, apples contain arsenic and cyanide. Concentration matters.