Everyone tries to say their breed is special... I'm sorry I don't buy it. I've known many and gotten to personally work with a few. Like with any dog same sex pairings are fine as long as a pecking order is established and you don't house two dominant dogs together. Dobermans by nature should not be dog aggressive.The part I quoted in your reply is very untrue in the particular Doberman breed, this goes for neutered or not.
Talk to any long time responsible breeder and many knowledgeable long time owners, you will hear the same. Many Doberman rescues also won't adopt out to homes with multiple males.
On that same note many have no problems living with multiple females at all. They aren't known for the dog aggression, like the males of the breed.