I agree that markets need regulations, I just fail to see the comparison between after-work e-mail and children in mines. I think it's quite ludicrous to compare the two.
Firstly, there is little data on how many companies require this sort of employee. My guess is that the few companies that do require it for good reason (would you really be okay with not allowing hospitals to page doctors after hours?). More likely, employees feel pressured when there is little pressure being exerted by the company itself. I've worked in strategy consulting which is well known for how it takes over your life. Most of my colleagues felt a compulsion to respond immediately that I simply never felt. If you listened to how they put it, you'd think God himself were breathing down their neck. This is completely self-imposed. The alternative is to respond when ready and before the deadline, but not feel pressure.
> Your view of "just go to the job tree and pick a new job" is cute but completely out of touch.
If your choice is between not having a job or responding to e-mail, then legislation isn't the way out. If your job requires this kind of attentiveness, and you have no other choices, making it illegal for your company to require this does not make your life better. It simply makes your job go away. We are seeing this right now with the rise of automation due to the increase in minimum wage.
The government needs to focus on giving employees skills so that they too have something to negotiate with. The fact is that an unskilled employee has no bargaining power and is little more than a slave. The government's strategy should be two-fold: (1) invest heavily in making sure every employee has a skill that can be bargained with, and (2) stop subsidizing businesses.