Your post is akin to telling a depressed person to stop being depressed. You can't just tell someone to stop having anxiety. That's not how the illness works.
It never goes away, you just get on top of it as something that you inextricably are, like having a scar or poor eyesight. its called emotional repression.
But not everyone does, nor can everyone learn it, people are unique and often incompatible with what works with other people in a way that cannot be changed.
You can't reasonably expect everyone to use the method that has worked for you, because your method is unique to you and in many cases is completely impossible to use for others, especially those with hard wired responses to trauma.