I strongly disagree.
In any situation involving a mass shooting by a criminal or terrorist, the first one that he will target is someone openly carrying a firearm. Carrying a concealed firearm says that the carrier wants to be able to take out a shooter before the shooter knows that he is armed.
Concealed carry also protects those who are not carrying. Where concealed carry is permitted and encouraged, criminals and terrorists have no way to tell if anyone is carrying or not. As a general rule, if you intend to commit a crime or a terrorist act with a firearm, you are not going to choose a location where your intended victims may be able to fire back. This is why mass shooters almost always target so called "gun free zones."
Mass shootings are extremely rare events.
The political threat to our rights is ongoing.
Carrying openly is much better for political purposes.
Carrying concealed has some tactical advantages.