What it means
Men who are going to be in confrontations have to be trained. Some have to get a 13 week session, some have been trained since they were old enough to talk, and others will get a combined dose.
What the training prepares you for is THE CONFRONTATION.
When you are suddenly thrust into a CONFRONTATION:
You do not have time to weigh the benefits and consequences of your reaction.
You do not have the time to try to verbally convince your confronter that he she should not try to overcome you or kill you.
Once you have been involved in a CONFRONTATION:
You will learn that criticism is certain. You will hear all kinds of Coulda, Woulda, Shoulda. People who never ever faced the possibility of having their ass kicked will be instant experts on use of force.
Psychologists will opine that you could have done several other things other than kill your opponent.
Wussies and women will call you a savage, and wonder how you became so brutal.
Legal experts, JAG Corps and attorneys, will debate what you did--If you did it legally, did you follow policy and procedure, or observe the Rules of Engagement. Often, to guarantee their own employment, they will charge you with a violation, and be concerned with the following trial or Court Martial. You, and a confronter, enforcer, or enforcer, can NOT consider this at the CONFRONTATION. Hesitation will give the advantage-however slight--to your opponent, and he will probably kill you.
So, in the minds of "Normal" people, you are a "rough man".
They do not want to BE you, do not want to do what you do, and feel free to offer criticism and accusation. Often, they are jealous as Hell of you. Regardless, your function of to save their ass.