Women like bad boys, meanwhile silicon valley is full of 40 year old virgins. Forced ascetics. The absence of women (lack of companionship for the forced ascetics (like klebold) or more perverse for the incels (cho, rogers, sodino)), tends to be what fuel most of these mass killers. While the parkland shooting was going on, online forums of incels were cheering him on.
It is not good for man to be alone. He needs interaction with others, especially women. Aristotle felt that what separated man from beast was his ability to use speech and reason. Society itself is very psychotic to people they don't like. Like a flock of chickens who insist on proving dominance by pecking to death the weakest members, only in the case of humans trying to get them to off themselves which is contrary to human nature. and for people it doesn't like they deprive them of speech, reason, and ultimately through ostracism the inabiity to interact with others. They deprive them of their humanity. There is only one way to reclaim your humanity when denied speech and reason, and that is to destroy your masters. As Nasim Aghdam attempted the other day. Only for Cruz, having been expelled, they were no longer his masters. It was likely an act of revenge, if he even done it at all. Most who do leave behind some form of manifesto to create hope for others.
Bullying is a severe problem, but bullying alone is unlikely to result in such chaos. Rather it is perpetual and never ending loneliness. Chronic isolation, especially for gifted people, can mess people up seriously: depression, anxiety, and embitterment. Then when they get put on anti-depressants/anxieties. It wasn't their own mental illnesses that was holding them back. and the removal of their inhibitions means they are more likely to unleash the beast and act on their embitterment they been storing up all their life. As Klebold said on page 482 on the columbine papers, "martyrdom is hope for others". It is also the same page he wrote a poem about how he is a god of sadness, denied the ability to find and have his love, born human but unable to be human. That resonated with so many, and created the Columbine culture.
Cruz is a rare survivor. So he gets to live both as a bad boy, and to some extent he has the support of the incels, and there are those who are driven to him by his fame. If he is able to get out of his legal situation through a finding of not guilty, or an NGRI (and release), the kid will likely never be alone again.