We don't normally discuss freedom in this way. The other things in the Bill of Rights - Speech, Right to Legal Counsel, etc., we never ask "why do you need to e

We don't normally discuss freedom in this way. The other things in the Bill of Rights - Speech, Right to Legal Counsel, etc., we never ask "why do you need to exercise that right?". So why would you ask why a state needs to exercise the 10th Amendment?