I'm going to call out my friend
For what reason why you would call your friend out?
My friend is not a good person.
If they're not a good person, then I do not think it will be healthy for you to continue spending time with them. Instead of calling them out, try to be more understanding and have a chat with them one by one to see if they can change.
You are a close-minded and I'm thinking about exposing him.
I do not feel like I am being close-minded, as I was just trying to tell you to be more weary of the situation and tell them first in private to see if they can change that way. Jumping towards "exposing" them risks you of being in a legal trouble with this person accusing you of defamation.