My dad once told me that if you stop replying to people’s anger they eventually stop the anger or take it elsewhere.
I would like to suggest that if you come across a rant or someone who seems very angry then you ignore what they have said and simply don’t reply.
Pattern: Angry person posts something. 5 people reply. Angry person posts again. 5 people reply. Angry person feels validated and starts a new thread. And so on ad infinitum.
Ignore the anger, and watch it die an impotent death.
Great fleas have little fleas upon their backs to bite 'em, And little fleas have lesser fleas, and so ad infinitum.