The connecting thread thus far between the various mass murdering incels has been autism. Autism is a mental illness that makes it hard to build emotional connections to other people. With no emotional connections to others, autistic incels see no value in their lives or the lives of others.
Killing is offensive to most of us because most of us understand the emotional repercussions caused by murder, based on our feelings for those we've cared about in our lives.
Autistic incels have no such connecting threads and are thus at the highest risk of mass murdering.
But as stated, no one has specifically gone on a Chad and Stacy mass murder rampage. The most famous incel mass murderer Elliot Rodger primarily killed men who were betamales at best.