It doesn't take reddit to consider the idea that a shooting where 4 people, not including the perpetrator, are shot can be considered a "mass shooting." The FBI uses a standard where at least 4 people are murdered. Obviously, you can have a horrifying mass shooting where no one actually ends up being killed.
This is the first post :
Later, this was stated to you :
"Mass shooting refers to an incident involving multiple victims of gun violence.[1] The Congressional Research Service acknowledges that there is not a broadly accepted definition,[2] and uses a definition of a "public mass shooting"[3] if 4 or more people are actually killed, not including the perpetrator, echoing the FBI definition[4][5] of the term "mass murder"."
https://en.m.wikipedia.org/wiki/Mass_shooting
It seems the Congressional Research Service would be a reasonable organization to define "mass shooting," so it seems like you're using a more narrow definition to associate with a smaller number. You're not disproving the fact he's communicating, you're debating that the terminology he used applies, you're complaining about how he communicated it. Well, he defined it for you already.
You can argue that the other definition is a more appropriate number, sure, but the number of "mass shootings" by the FBI definition is still alarmingly high.