I think there's more variables to it than that. It's absolutely possible to create aggressive drivers out of thin air if you annoy everyone around you enough. I used to drive commercial equipment that simply couldn't keep up with normal traffic. Needless to say when you are a rolling obstruction you see a ton of "aggressive" drivers because "normal" drivers do aggressive stuff rather than get stuck behind you. I can't imagine how bad it would be if I were driving like that in a vehicle that didn't very visibly have an excuse to be acting that way.

If they are not detectably different from good drivers, doesn’t that make them good drivers?

The aggressive drivers I personally know are always aggressive.