The extremes that we are talking of leaving behind are extreme of reaction to a chosen lesson. What you are being asked to leave behind is the need for such lessons.
If you have learned the curriculum, what further lessons are needed? What quite knowing cannot come to you in peace?
Why would you believe you can learn from the turmoil of extremes what you cannot learn in peace eternal?
~ Christ, A Course of Love T1.10.12
Are you being asked to give up extremes? Yes. You are being asked to give up all that would take peace from you.
But as you have been told before, you will be giving up nothing.
It will seem if it is so for a while perhaps. You will continue to be attracted to those living at the extremes and there is no reason not to take joy in observing another’s happiness or to feel compassion at another’s suffering. But you need not partake and you cannot partake if you are going to carry the Peace of God with you.
~ Jesus, A Course of Love T1.10.7