I don't even understand why he has to be asked to resign. Common decency should have caused him to leave on his own. There are kids with high concentration of lead in their bodies because of the incompetence of his administration. This will affect brain chemistry and behavior going forward. These kids are already at a disadvantage because they are poor and now more than likely, they will have to deal with health issues for life. Maybe a class action law suit will get their attention.
Most sources I am reading have suggested that Gov. Snyder was aware of the water crisis before it became public for an extended period of time. If it can be confirmed that this is true - that the Governor held on to this information well before taking action, Snyder may well have broken the law and thus would no longer be qualified to serve in office.
The root cause of the Flint water issue was a decision by the city to temporarily stop using Detroit's water in an effort to cut costs. Michigan's environmental agency should have stepped in a lot sooner, instead of insisting the water was safe. The EPA has not helped, and the President has been slow to act. Unfortunately, mismanagement at so many levels of government is going to cause taxpayers to foot the bill at the state and federal level.
One can criticize, but few, if any, states' governor likely has the experience to have handled the situation well. I don't think it calls for his resignation. I would like to see him quickly do more to clean up the water poisoning. The EPA and the state's environmental agency should take the lead on clean up under his directive and with his full support. Until cleanup is achieved, the current plan of trucking in bottled water and having the National Guard distribute it works to keep people healthy.