As always, all dogs are individual and react in different ways accordingly. I would, however, agree in general.
I have worked with many kenneled dogs as well as pet dogs. Dogs, especially when castrated, in a two dog situation tend to sort out the pecking order and live with it. Two bitches that really decide that something needs to be sorted out between them can keep up the bad feeling for years!
In dogs it is usually apparent pretty quickly which is the more powerful animal and the weaker saves his skin by being submissive. Bitches that fight seem to take a lot longer to decide who is the weakest, they are more determined and they NEVER forget!
Stud dogs are an exception in that they have something to fight for and it is totally natural to go all out in that environment to win.