A sick deranged person did the vegas shooting with or without help and for a motive we can not be sure of.
Your problem is you see demographics and not people. To help you, please tell me how many "white males" there are and how many of them have done mass shootings. I will further help you,
Although I am not sure how accurate a simple google search says there are 233,000,000 white people in the US. Lets say that there are 100,000,000 males. Lets get rid of most of them as too old or young. and lets just make it 10,000,000 white males currently in the US currently. Plus of course more historically.
Now, how many mass shooters have there been in the last 100 years and contrast it with 10,000,000 people plus and tell me why talking demographics and talking about it as a characteristic of a demographic means anything.
Again to help. It has averaged about 2 a year in recent years.
http://www.msnbc.com/msnbc/mass-shootings-have-become-more-frequent-the-1970s
Sick murderers are of all races but mass shootings are rare. It really is crucial to find out what causes killings whether its mass, bombing, serial, gang conflicts and how we can change it through social and law changes. Mass killings are just the most graphic and startling but the same can be said of gangster shoot outs and drive bys that kill collateral targets or serial killers who kill people without motive to kill that person.
Trying to isolate the demographic is to try to say that something about the 2 people a year who do mass shootings that does not cause the other 10,000,000 to do the same says more about you than about the demographic.