To be fair, the number of mass shootings has indeed increased, depending on where you set your starting point. And quite certainly the severity of the mass shootings has gone up.
Overall gun violence (and crime, including violent crime) is down, but that doesn't make the news.
It's like the massive coverage given airplane crashes producing the impression that airplanes are more dangerous than cars, when the opposite is very much the truth.
The media's focus on mass shootings is no doubt partly driven by anti-gun ideology, but it is fairly obviously driven even more by the news value and ratings possiblities of these stories.
Nobody tunes in to see a story about somebody not getting shot in Cleveland.
Part of the driver of this sort of thing is rampant “old fogeyism” - the idea that ALL things used to be better but everything is now steadily going to hell. It’s a sickness that Conservatives are particularly prone to.
The other thing that people have a false impression of is that the world is more peaceful now than it has ever been in human history - the chance of an average person dying violently has NEVER lower - be it murder or war.
The human population has grown exponentially into the multi-billions but war between states has become practically non-existent. You have some civil wars but the death rates are pretty low compared to history (20 million people died in the Chinese Taiping Rebellion, out of a much smaller population, in the 1850s-60s.
And terrorism just doesn’t kill many people. But it gets media coverage.
The perception that the world is sinking into widespread war is also fueled by the End Times Apocalpytikook frauds, shysters, and liars. They try to exploit the gullible by simply listing some wars or possible wars (without the context of how the world was MORE violent 100 years ago and 1000 years ago).