Earlier quoted context omitted.
Defamation, Slander, etc. None are protected. Free speech protects you from the Government, not your fellow citizens.
The court is part of the government.
Example: I specifically prohibit peanuts in my kitchen, because I serve meals to allergic children. You sneak peanuts into the kitchen. I sue you and win.
Does this mean "Peanuts are illegal"? No. I have a civil action and we have a system of civil courts wherein these grievances can be aired and adjudicated.