May I chime in? Good. ;^)
One of the main reasons we homeschool is because of our religious beliefs. I want to make sure that my kids get grounded in their faith before they are sent out to face the wolves.
I had a friend use this illustration: When you are growing a new tree you don't set it out, as a seedling, in the middle of a hurricane thinking that the hurricane is what the seedling needs in order to grow into a stronger tree. What that seedling needs is to be sheltered, nourished and cared for, then when it is strong enough to stand the winds you put it outdoors.
I view my children the same way. As young children, actually as young believers (they have all told Jesus that they believe He died for their sins and rose again and they have asked Him to be their Savior), they are not strong enough to face what the world tends to throw at believers, especially young ones. So it is my job to ensure that as well as knowing reading, writing and arithmetic, they know their faith as well.
I am not "shielding" them from the world. They get exposed to it everyday as they watch videos, as they visit my relatives (who are not Christians), even as they interact with their heathen friends (joke!) at church.
We are nurturing our children so that they will be strong enough to stand when they are finally out in the world on their own.
-Kevin