Happens here it's likely terrorism, happens there its likely just another run of the mill mass shooting.
Gun violence is passé there. It's part of the culture. In 2015 there was over 30,000 deaths by firearm in the US, in the UK there was 51. More people are typically killed with guns in the US in a day (about 85) than in the UK in a year.
Since John Lennon was murdered in New York in 1980 more than 1.2 million have died by firearms in the US.
My brother lives in Texas. The only thing I envy is the weather. He can't gamble (not even online as the IP address prevents it), can't drink unless over 21, yet he can walk into a store and buy a gun. Coming from outside he knows it's madness, but when you are brought up in that environment you don't know any better. Any petty argument can ignite into something deadly. A bad day at work or just a low episode of depression can end up by putting the gun to your head. When you make something so easily accessible there is a greater chance you will use it. The argument by backward gun nuts is "guns don't kill people, people do"...by that logic heroin doesn't kill people, let's have it freely available too then. Right wing folk by nature are opposed to change hence are backward. They revert back to the words of a group of slave owning white supremacists from the 1790s, which ain't surpising as slavery itself would still be around if it was up to right wingers (so too would white only citizens, privileged white male only vote, white only immigration and other supremacist laws from that era). Liberals have effected most of the changes there (the death penalty still stands) but I don't see them making any inroads in the gun law.