Why is it rare for a bystander to intervene in a mass shooting in the U.S.?

 The main reason is that the laws regarding all this are very tricky and vary from county to county and from state to state.

For example, I live in California where you probably might go to jail if you did what the young man did in Indiana that was armed and licensed to carry his firearm in public. Why?

Because generally speaking police don't want vigilantes to be shooting people because mostly they are not trained for it so bystanders might be shot by accident. Luckily, in Indiana the man was only 22 and likely had good reflexes and was young enough and licensed and so he got away with this.

However, I wouldn't be surprised if some states made laws protecting legally armed bystanders to shoot mass shooters especially in the climate the U.S. is in now.

Why?

Because we have had at least 300 mass shootings so far in the U.S. since January 1st.

But, let me share with you how it is in California regarding all of this. But, even then it would vary from county to county throughout the state depending upon local laws.

For example, if an intruder came into your home in California you could legally shoot him IF he had a loaded pistol or other firearm that he was pointing at you intending to shoot you. If you shot and killed him then you might not have to go to jail here in California.

But, if the intruder had only a knife or a club or other weapon (not a rifle or pistol) you might go to jail if you shot him. (it would depend upon many factors).

But, if a mass shooter was in a mall I don't think a California resident would be allowed to shoot the mass shooter under present laws because the police here don't want bystanders shooting people generally speaking. I suppose there might be a county or counties where you could do this without going to jail but I'm not sure which ones at this point.

But, if you were a father or a husband and someone is shooting at you and your family I'm sure you would draw your licensed weapon and take them out no matter what the consequences. And then also if you were protecting your family this takes it in an entirely different direction too which also might protect you in a court of law. But, it is very uncertain at this point which way things would or could go at least regarding the court system in courts throughout California.

This is why a bystander drawing a licensed weapon and shooting a mass shooter is unusual in the U.S.

Because there are as many ways to look at this as there are states in the U.S. (at least legally speaking).