Ok since you lack basic reading comprehension I'll quote it for you.You've only addressed the problem in Mexico. Which is OBVIOUSLY like the US, France, Germany and UK.
The majority of these mass shootings (which are defined as a shooting that results in 3+ deaths) are related to violence in a very specific place among a specific group of people. Whether that's due to gang violence, poverty, oppression etc I'm not here to argue but the point is the issue doesn't lie in guns but in the demographics of who owns those guns. The lions share of these shootings can be attributed to one specific group, not the whole of gun owners.The majority of gun related crimes (especially homicide) is black on black (and sometimes black on white) violence in majority black areas. A lot of the time involving gang related activity. So it's not an epidemic of random people walking around and lighting up schools all the time. It's generally blacks shooting other blacks. I'm going to get crucified here but that's what the stats show. Don't shoot the messenger.
http://www.brookings.edu/blogs/soci.../2015/12/15-guns-race-different-worlds-reeves
http://www.nationalreview.com/article/420565/charleston-shooting-obama-race-crime
http://www.amren.com/news/2015/07/new-doj-statistics-on-race-and-violent-crime/