Well, they found themselves a potential scapegoat. Snyder was not well liked as a Republican mayor in the largely Democratic areas of Detroit and Flint. The truth of it is though, he did a pretty good job everywhere but Flint. He got more good done in Detroit than anyone else in my lifetime. The improving trajectory Detroit is still on is largely because of Snyder.
...But, he inherited a turkey in Flint's water system. A lot of people want to put the blame on switching water supplies. And, in some ways, that was the straw that broke the camel's back. But the truth is, the pipes under Flint have been leaching lead since at least the 80's. Every one of the water pipe quality tests for Flint had an asterisk by their "Pass" grade. That asterisk? It was for an improper test procedure. They'd shock flush the pipes a few days before testing. So Flint people would have orange tap water three days before the test because all that contamination had just been flushed out. And causing that giant spike would "push forward" and flush out just enough contaminants to temporarily lower the current contamination numbers enough to get a passing score during the test.
So, the pipes were deemed safe, and everyone was happy. Except for the residents who have to have orange water before every test, and get back to unsafe water a week or so after the test. But Flint isn't a happy place anyhow, and anyone who has any political importance isn't living in Flint, anyways. Because they already know all this, in addition to the crime and decay problems. So it's all good.
Flint used to do their own water processing ages ago. But the Flint River was pretty contaminated, and with declining population in both Detroit and Flint (and the associated declining water demand) it was determined that Flint could just use Detroit's water processing, instead. So this was then the happy situation Snyder inherited when he started.
A double-whammy happened in Detroit's water needs. A couple of exceptionally cold winters burst pipes in abandoned commercial buildings that hadn't had water service removed. And either no one was inspecting these buildings or the reports just didn't get water shutoff to them. There were tons of rumors and pictures of buildings with water just flowing through them and pools feet deep in the foundations. Tons of wasted water. And, with some residential and commercial pickup in Detroit, itself, there was a legitimate need for more water, as well.
Detroit processing couldn't supply both Detroit and Flint, anymore. So the decision was made to make improvements to the Flint River treatment plant and reopen it. And, after some initial hiccups, that was done, and the plant was shipping out well-tested water with a more neutral pH than Detroit's processing was. Happy days, indeed! So we have "passing*" pipes in Flint, and actually good water. All is good, right?
Well, no. First test, they actually used the legitimate testing procedure. No one shocked the pipes beforehand. Of course they failed that test spectacularly. Here comes the national attention. So finger-pointing all around. The "change" was the water source, so that got blamed. The Flint river is poisonous. How could Snyder do this to us? That plant was closed because it couldn't provide clean water years ago! But the Flint river is cleaner now than it was then. It actually supports fairly normal wildlife, at this point. I wouldn't eat the fish from there. But I wouldn't eat a channel catfish or anything else low in the Detroit River, either. Doesn't mean they can't safely process the water, though. And the improvements they made to the Flint plant meant it was actually producing better water than the Detroit plant was. But that isn't headlines, so pretty much no one mentions that little wrinkle.
So, it was quietly proven that the water leaving the Flint plant was fine. Uh-oh. Big pow-wow. The problem is the pipes. (No shit, really? Everyone paying any attention already knew that one. Why else were they shocking them before the tests in the 90's and 2000's?) So, they finally managed to sneak through a shock and then retried the test... "We've made changes. It's all safe, now!" ...And still failed, though much less. Even more national attention. But it turns out the better water leaving the Flint plant (more neutral pH) was causing more leaching than Detroit's water was. So while it was tested and proven to have left the plant better than Detroit's water, it was still worse by the time it reached the overall testing faucets.
And then came the calls for digging up the pipes and everything else. Very little of that actually happened, and now it's largely forgotten about, again. They modified the pH of the water leaving the Flint plant, and managed to squeak back into an asterisk "Pass" sometimes, and that is where it all stands, now. Yay, fixed! It's all safe, now! The tests* say so!
Sure, Snyder was negligent on some aspects of the crisis. And he makes a great figurehead for some narratives. But he really just bumped into a hornet's nest that no one wants to admit (still) exists.
