There were lots of "good guys with guns" at Uvalde. It was some time ago, but I recall an FBI statistic that said that for every instance where a gun is used to protect the residents of a home, there were some 40+ incidents where that gun was turned on the residents. The problem in the US is not just guns, but a culture based on zero-sum competition to the death resulting in fear and loathing of each other PLUS guns. My brother who is a cop said that ever trained cops will fire 10-15 shots for every shot that hits a target. Civilians with firearms would be way worse than that.