The "Everybody should be armed" narrative is spread by people who can't even properly justify their reasoning. They always throw a "they should have been armed and they wouldn't die" or something as dumb "all school staff should be armed". I learned to ignore them and their wild west fantasies.
Good idea. I've found the best way to engage (if you want to engage) is to just take the argument seriously, and ask what kind of society they envision, in detail. It gets awkward quickly.
There's a subreddit that lists news stories of self-defence situations with a firearm. They don't make the news because they are all local stories but it happens all the time.
The idea that the US can somehow turn back the clock with hundreds of millions of legal guns already purchased is laughable. Almost every attempt at the state or city level has completely backfired. That train passed long ago. And the denial of this has only ever worsened the problem. I'd go as far as saying it's an anti-science position in 2020.
An aggregator of stories on a given topic can make anything seem to happen frequently. This would, by design, ignore any stories that don't fit the narrative. It may be a good source for stories on that exact topic, but is by no means an accurate indicator of frequency, especially as a sole source.
Unless you correct for education, wealth distribution and Asher things like gang affiliations that's be selection bias too; there's just much more than "firearms deaths/firearms ownership" going on.