I'm pretty sure I've been told my state is a right to work state. Hmmm...well, I work for a good company and the one before that was huge and had many policies and procedures in place, so that seemed ok, too.
A lot of times large companies have headquarters that are in union states. So, their employment policies tend to be based on what will be acceptable in their "home" state.
It's a better deal a lot of times for employees in other states than if they went to work for one of their local companies.
And some companies are simply better to work for than others. And some industries are better to work in than others.