You seem to ignore two things here:
1. No one on this thread said anything of the like regarding your first paragraph
2. Your question about why threads aren't started when gang shootings happen has been answered numerous times by a few people.
What's interesting about your point is that it's a non sequitur fallacy. The two aren't correlated but you constantly beat this drum and try and make a correlation.
There are existing gun laws and criminal statutes that deal with shootings related to criminal activity and gang violence. Clearly, banning gun types and everything tried in these cities has not curbed the violence. The symptoms are being treated but the illness hasn't been diagnosed.
With mass shootings in schools, I'm sorry to say because the street violence has occurred for so long, it doesn't make the news anymore but these school shootings do because they are abhorrent and the true definition of evil. It is a sad state of affairs that 20-30 people shot in a weekend in Chicago doesn't move the needle anymore. I don't know what to tell you other than most are numb to the violence.
I hope and pray that you never have anyone you knew and spent meaningful, impactful time on this earth be a victim of a mass shooting, because I can tell you it's extremely painful. Two of my professors were killed at Virginia Tech. Every time another one of these school shootings happens it brings me back to 2007.
There has to be a middle ground where we can figure out something to try and prevent these mass shootings. Again, I agree with you, the gun is a symptom, not the diagnosis. But we've got to figure out a way how we can make an attempt to try and stop these shootings. Freedom to own guns is something I agree with, but the killing of innocent lives, children over and over and over has to at some point be too much for a pure 2nd Amendment right with out some slight impingement. I don't think it's too much to ask to have elected officials sit down together, take all the information on, and have a rigorous debate and a practical solution where both sides have some give and take.
There's no Panchaea magic legislation that is ever going to prevent mass school shootings. But if well crafted, thought out legislation can be brought forth and it prevents even one of these events occurring, then that's a win. I'd like to have that happen before we to become numb to elementary students being murdered at schools.
Originator of the Tony Adams Scale