The issue has nothing to do with video games in reality. These things happen because of a few things.

Mainly it's because of the mentality of these people. There needs to be some sort of free help to get if you need psycological help. It could possibly prevent a lot of loners ending up killing people, or going on a rampage.. or even suicide.

Secondly. The media is also responsible in the way they portray horrible things and exagerates as if they were as common and normal as could be.

Guns are also too easy to get a hold of. I know this in particular revolves around knives but it's still a issue.

violent crime actually isnt as big a problem in the UK as you might think, its just the way the Right Wing media covers it, i think crime is actually going down here (i think, dont remember the figures from the news months ago)

Reminds me of the sin tax. I never really understood why it is a sin to drink a beer or two. Just getting buzzed isn't a sin and is even stated in the boring Bible.

http://news.icm.ac.uk/business/uk-crime-levels-%E2%80%9Cfall%E2%80%9D-according-to-survey/572/

http://www.crimereduction.homeoffice.gov.uk/statistics/statistics074.htm

both say crime is going down