The point being, in my view, parent's are supposed to prepare children to be adults, functioning members of society.

If your kids sleep for 8 hours a day, go to school for 8 hours a day, spend 2 hours getting ready for school and driving back and forth, then have to do homework for an hour every night that's 19 hours. The parents only get 5 hours to feed them, play with them, how them do chores, and teach them. How are they supposed to prepare them to be adults?

This is not achieved by coddling them and preventing them from learning the skills necessary to overcome adversity.

You are dealing in absolutes. A parent homeschooling is coddling and a parent that sends them off is preparing them. Is there no middle?

I homeschool my kids, we have a co-op with 3 other families. There are about 25 kids total of varying ages, there are 3 moms there to help teach, play, and monitor. Each parent knows their children better than a teacher teaching 300 different kids every year.

The parents can discuss and let the kids play and let them resolve their own issues, but there are also enough of them and they are all well informed enough about how their kids act to make sure any adversities or bullying is helps the kids (working things out on their own) before it becomes hurting (fighting, self-esteem issue).

That's not coddling, if anything it's more balanced than a teacher that can't possibly watch all the kids all the time and know how to react to every situation. There are too many legal issues to worry about.

Or is it wiser to teach your children the tools that can only be learned through adversity. Teach them how to handle bullies, drugs, sex, violence, in order to equip them for adulthood?

It is wiser to do these things, and these can be done in a controlled homeschool environment.