Amid denials, state workers in Flint got clean water

It's a total fudge, basically. But even if it weren't:

So should people have been panicked and drinking bottled water there for most of the last 30 years?

The problem with what you're asking (and perhaps the biggest problem with the MJ article you cited) is that in past decades, lead poisoning (as measured by children's blood levels) has come from multiple sources (lead-based paint in homes being the most widely cited culprit). So it's an apples-to-oranges comparison to start with.

And any numerical "extrapolations" from those numbers to what the comparative risk factors from water sources might have been, going back decades, are equally vacuous.

How would that have looked to the people who actually voted for them tho.