That's because entire entire societies are build on the concepts of bravery, strength, ability, manhood and honor, at least in theory.
Hard to see how early societies could have survived in any other way. However, did you know that among the Plains Indians there was some provision made for males who didn't measure up to the expected standards? They had no honor and didn't run with the braves, but weren't persecuted either. When the real men went out hunting and fighting, they stayed home and took care of the squaws.