I'm going to warn people away from my ex
Are you serious? Why would you warn people away from your ex?
They need to know what a dirtbag he is.
I know that you didn't get along with your ex, but saying bad things about him to others to hurt him is wrong. Mind your own business and stay out of your ex's.
You don't know what he did. It's my job to warn people away from him.
It's still wrong to make sure that he never dates again by warning people away. You should just forget about him entirely and let him live his life.