For the most part it is common practice. How ever you may have times when you do not have the facilities to do so. IE: Port-a-pot, going in the woods, etc.
I guess they think that they do not have to? Maybe they want to spread disease?
you should wash them before... Hell knows where our hands have been.. However, I do agree with you, I hate it when people don't wash their hands.
I always wash...