I think it may be partially rooted in 'stuffed' (repressed) anger. Take a kid (male or female) that grew up in a bad family... or had no family... or was the object of bullies... or a host of other less than positive environments. They can be sub-consciously programmed to react to certain behaviors, especially if focused on them. When that stimulus happens, it tends to receive an aggressive (whether or not physically violent) response... which is more reactionary than carefully chosen. And this 'scenario' is exacerbated by the idea that it is not 'cool' to be gut level honest with one-self and deal with the inner pain.
OTOH: And IMO this may start a new discussion: Are we as a society being programed to abhor violence too much? Please do not hear me saying violence is a good thing... only that when folks get an anti-violence attitude... they tend to throw out the baby with the bathwater so to say. Examples may be gun control, this anti-bullying campaign, assuming crime can be stopped with therapy, etc.
A conversation for some thought, if anyone is interested... Problem is... it may well step on toes.... which usually causes lack of interest.
Side note: Over at the aviation forum I post at... they are opposed to all forms of political discussion... they say it is negative... Yet a handful of folks can stomp all over the rest of the posters on aviation issues, acting literally like internet bullies... and complaints are ignored. Seems we take our definition of what is right and wrong with a grain of salt... and perhaps we sometimes are hypocritical about the underlying cause.... IMO that being an attitude problem... which is a choice to repair.