This comes across as rather crass - a rather poor start to an article that doesn't do justice to the subject. You are correct in establishing that this is an epidemic among cis white men. The Republican obsession with demonising trans when it comes to mass shootings is both extremely offensive, purile and complete nonsense.
Yes this is about power but what screams out from these tragedies is powerlessness. The men who commit these terrible crimes are mostly motivated by a sense of emasculation and hopelessness. That doesn't diminish their crime or mitigate the pain they cause, rather it speaks to the power obsession of the patriarchy that has poisoned our society.
The bottom line is that America is breeding mass killers and providing the tools to carry out their crimes.