Can I tell a now ex-friend how they were treating people is wrong?
Do you think it would help?
Maybe not, but it will feel good to say it to his face.
It's good to point out harmful behaviors that you see in others, especially if it hurts those you know. You may be the first person to let your ex-friend know that how he treats people is wrong. Hearing it would be a real wake up call for him.
But I'm not looking for an argument with him.
I know you are not, but it's something you want to get off your chest because you are a moral kind of guy. I am proud of you for taking a stand for what you believe is right. I am sure your ex-friend doesn't deserve to be your friend.