It's modern bigotry and hatred - like the term "redneck". It's more reflective of the fears of "normal" gamers of what they themselves might turn into unless they properly prepare themselves beforehand by "identifying the threat" and making sure not to become it than anything real.
This isn't to say that humans don't have problematic elements in their lives. So a frustrated teen might take out his frustrations in a CoD match as his ancestors might have alternatively done by going to a gym and beating on a punching bag. Someone upset about this frustrated teen might call him a "dudebro", which doesn't solve any problems and mostly serves to drive a wedge between people who could otherwise help each other.
The only serious concept of "dudebro" I'm aware of is the potential of rising fascism, as Europe is experiencing at the moment. If a culture of young men develops of unity excluding women, minorities, homosexuals, and the like, this could expand into fascism. It's very difficult to judge how much of a potential problem this is in the United States at the moment.