Despite your claim, that's not what I said. Other countries have mass murderers, too. In fact, on a per capita basis, the USA is not the worst country for mass murders by shootings by far. Not a great thing to brag about, but it's the truth.
Also, if you think mass shootings are limited to the USA, you're sadly mistaken. We've had our fair share, but this killing spree phenomenon is not specific to the USA.
Rank Name Location Year Victims Killed
1 Garissa University College Attack Garissa, Kenya 2015 148
2 Peshawar School Massacre Peshawar, Pakistan 2014 149
3 November 2015 Paris Attacks Paris, France 2015 130
4 2011 Norway Attacks Oslo, Norway 2011 77
5 Westgate Shopping Mall Attack Nairobi, Kenya 2013 67
6 2017 Las Vegas Shooting Las Vegas, Nevada, USA 2017 58
7 South Korea Shooting of 1982 Uiryeong County, South Korea 1982 56
8 New Zealand Mosque Shootings Christchurch, New Zealand 2019 51
9 2016 Orlando Nightclub Shooting Orlando, Florida, USA 2016 49
10 Sousse Beach Mass Shooting Sousse, Tunisia 2015 38
11 Port Arthur Masacre Port Arthur, Tasmania, Australia 1996 35
12 Virginia Tech Shootings Blacksburg, Virginia, USA 2007 32
13 Tian Mingjian Incident Beijing, China 1994 28
14 Sandy Hook Massacre Newtown, Connecticut, USA 2012 27
15 Sutherland Springs Church Shooting Sutherland Springs, Texas, USA 2017 26
16 Kampala Wedding Massacre Kampala, Uganda 1994 26
17 Luby's Shooting Killen, Texas, USA 1991 23
18 San Ysidro McDonald's Massacre San Ysidro, California, USA 1984 21
19 2015 Bamako Hotel Attack Bamako, Mali 2015 20
20 2010 Chihuahua Shootings Chihuahua, Mexico 2010 19
21 University of Texas Tower Shooting Austin, Texas, USA 1966 18
22 Dunblane Massacre Dunblane, Scotland, UK 1996 17
23 Erfurt School Massacre Erfurt, Germany 2002 17
24 Stoneman Douglas High School Shooting Parkland, Florida, USA 2018 17
25 Hungerford Massacre Hungergord, Berkshire, UK 1987 16
26 Winneden School Shooting Winnenden, Germany 2009 16
27 Columbine High School Massacre Columbine, Colorado, USA 1999 15
28 Edmond Post Office Shooting Edmond, Oklahoma, USA 1986 15
29 Toulon France Shooting Toulon, France 1995 15
30 Zug Massacre Zug, Switzerland 2001 14
31 Luxiol Massacre Luxiol, France 1989 14
32 2015 San Bernandino Attack San Bernardino, California, USA 2015 14
33 École Polytechnique massacre Montreal, Quebec, Canada 1,989 14
34 Pashupatinath Temple Shooting Mandsaur, India 1983 14
35 Aramoana Massacre Aramoana, New Zealand 1990 13
36 Fort Hood Shooting Fort Hood, Texas, USA 2009 13
37 Binghamton Shootings Binghamton, New York, USA 2009 13
38 Baku Shooting Baku, Azerbaijan 2009 13
39 Velika Ivanča Shooting Velika Ivanča, Serbia 2013 13
40 Kamwenge Trading Centre Shooting Kamwenge, Uganda 1994 13
41 Aurora Shooting Aurora, Colorado, USA 2012 12
42 1999 Atlanta Shooting Atlanta, Georgia, USA 1999 12
43 Rio de Janeiro School Shooting Rio de Janeiro, Brazil 2011 12
44 Campinas Massacre Campinas, Brazil 2016 12
45 Cumbria Shootings Cumbria, England, UK 2010 12
46 Charlie Hebdo Shooting Paris, France 2015 12
47 2011 Rio de Janeiro School Shooting Rio de Janeiro, Brazil 2011 12
48 Washington Navy Yard Shooting Washington, D.C., USA 2013 11
49 Geneva County Massacre Geneva County, Alabama, USA 2009 10
50 Bombo Shooting Bombo, Uganda 2013 10
51 Kauhajoki School Shooting Kauhajoki, Finland 2008 10
https://nypost.com/2018/08/30/america-doesnt-actually-lead-the-world-in-mass-shootings/
https://www.investors.com/politics/...-s-isnt-the-worst-country-for-mass-shootings/