Critical thinking is essentially learning to ask good questions and also caring enough to follow the threads you find.
For example, if mental health is to blame for school shootings then what is causing the mental health crisis and are we ensuring that everyone has affordable access to mental healthcare? Okay, we have a list of factors that adversely impact mental health, what can we do to address each one? Etc.
Critical thinking isn't hard, it just takes time, effort.
I just read a story where a cop visited someone based on a noise complaint and ended up gunning the young Airman down while he was on a video call with his mother and gf... So from my perspective, cops are the danger.