Chuck's son had once been a moderately popular author, ghostwriting for Breitbart News's "Milo Yiannopoulos" character during their Gamergate event. However, it turns out Breitbart had been paying in exposure, and working for exposure when you're not allowed to even put your OWN pen name on your articles doesn't actually pay the rent.
So Chuck's son lived in his parents basement. Breitbart retired Milo after poor critical response to the pedophilia story arc, and the kid went on to lesser things - in this case, advertising pizzagate on an obscure far-right blog. Eventually, Chuck got tired of hosting a cryptofash propaganda mill and said he wanted his son to move out.
By this point, the kid had drunk enough alt-right kool-aid that he decided "being expected to get his own place to live" was leftism and/or pedophilia - so he stabbed his father to death.
Below: Ethan Ralph, owner of the alt-right blog Chuck's killer was writing for at the time.
