Once you get used to carrying, you start noticing it everywhere. You see outlines and prints you probably would have missed before. It is not about judging people, it is just that you cannot unsee it once you know what to look for.
When I was in Law Enforcement, I took a class on "Identifying an Armed Individuals". It is a good skill to have as a CCW holder as awareness is key to situational awareness. Here is a good resource: https://calibrepress.com/2019/10/how-to-spot-armed-suspects/
If you carry for a while, you'll start noticing other people's printing, well, everywhere. Once you see it, you can't really unsee it. I'm not judging, just observing, you know? It totally changes the way you think about keeping things hidden.