Most voters aren't informed. Despite all the information being available no one looks at it. For example, when I fill out my California ballot once every two years, I spend a day reading all of the new proposed laws and reading on the backgrounds of all the people. Then most of my very intelligent friends just ask me to tell them how I'm voting and why, because they don't have time to read.
And that's once every two years. There is no way I'd have time to do that for every law. That's what politicians are for -- to be experts on the law and to hire other experts to inform them.
It's far too complicated to possibly be well informed on every issue.