Years back I got bit by a dog at the animal shelter but I had so many layers of winter clothes, there were no punctures. However the bruising was so bad it took 6 months before I could squeeze my arm and not have it hurt. My entire left side was a rainbow for several weeks!
I think two intact males is always a risk, which I knew going in. Especially in my case having two intact males, quite close in age (Pan turned 2 on Thursday and Nikon turned 4 around the same time), and living in such a small house/property without a way to kennel. If I lived in the suburbs I would have a kennel outside or garage/outdoor kennel runs. I don't like purely outdoor/kennel dogs but Pan is a dog that is actually more independent for a GSD and doesn't mind spending hours outside by himself. But because of where we live it's just not realistic. Phil and I decided before we had Nikon even that we will not put up with dogs that can't live peacefully. In this case it was really an easy decision. My friend is better suited for Pan's temperament, and honestly I probably would have sold him even if Nikon and Pan were still best friends. Yes there were indications earlier that Nikon and Pan were not going to work out but I did not expect it to escalate THAT quickly. This was Nikon and Pan two days before their first fight.
They have never really been friends though. Nikon, though he is protective of me and usually aloof with other dogs, is VERY tolerant with puppies so he's always been great when I have a puppy/foster/friend's puppy come over. He showed Pan the ropes when Pan was a baby but beyond that they just sort of coexisted as if they tolerated each other and at times would do nice submissive things like liking faces or acting like in that picture. I would say that Nikon was more protective of Pan as part of his pack than he was his friend. Pan has always pestered him relentlessly; he has high prey drive and a very low threshold for it (which means he's interested in anything that moves) so he always chases Nikon around nipping at him and for the most part Nikon just ignored him.
I believe what prompted the escalation to fighting is Pan's maturity. GSDs mature very slowly and if I had to guess when a problem would surface it would have been exactly this time. Pan has always been very social with dogs and people and not at all protective of me or defensive but that's actually not correct behavior for a GSD. I think he just didn't really know how to act when his hormones finally kicked in.
It's hard because *I* own and handle my dogs, if that makes sense? Phil is just sort of there. If my dogs are fighting and there's any hope of intervening, we either have to physically wrestle them apart or hope that they both decided to listen to me and knock it off. Before the fights, Pan started doing this thing where if he was near me and Nikon started to come over, Pan would hackle and give a low growl. Nikon would usually growl back but turn away to avoid a conflict. I would verbally and physically correct Pan and then prevent him from being near me for a time. It was like a resource guarding of me but in this case neither dog is really right or wrong. When we had the couple of fights, they were always instigated by Pan but would have been finished by Nikon. He won't start a fight but he's not going to let a little punk tell him what he can or can't do in his own house!
This is not a dominance/alpha thing; that theory is outdated and debunked. The other problem is that Pan has always had trouble figuring out "no reward markers" if you're familiar with training theories, and why he doesn't earn something. So say he starts growling, Nikon growls back, and then Pan can't just take that correction and move on he gets overly defensive about himself. He's a great dog and fun to train but he's also dumb, in a way. He's not very good at problem solving and he tends to go into a frantic state of drive (whether it's food, prey, etc) so quickly that he can't ever figure out why he's in the situation he's in and how to fix that. By contrast Nikon is a thinking dog, easy to "freeshape", a great problem solver, much more calculating and discerning with how he approaches a situation that might involve conflict or stress.
Also there is the breed aspect. No offense but unlatching the jaws of two fully grown male German Shepherds is quite different than breaking up to Shih Tzus. These dogs are bred to literally crush a threat. Pan especially is known for the power behind his bite. That's one of the reasons I bought him. When they bite for real they use their entire mouths and crush with their molars. If you get in the middle of that by accident you don't have any bite inhibition their to save you (for example sometimes I tease my dogs by pinching their toes and they play-bite by putting their mouth on me but obviously are using bite inhibition). Pan would probably be missing an ear if I hadn't stepped in eventually.
So anyway, to answer more succinctly I would say it really depends on breed and how the breed matures. I know nothing about Labradoodles. Pan and Nikon now hate each other's guts but are both fine with Coke, fine with all my foster dogs, and Pan is fine with all the dogs in his new home including another intact male GSD. If the dog is neutered young that makes a huge difference. Coke is not even considered a male to Nikon. I watched him the other day sniffing Coke's pee and Nikon was drooling and chattering the same way he does when he is scenting a bitch, lol. Most people I know have two or more male dogs in their home but most of them are neutered and were neutered pretty young. I don't alter my dogs unless there's a reason to do it so that changes the dynamics quite a bit. Would I get another male GSD? Oh for sure! I'm not actively looking and not because I'm sour about this whole thing - not at all - I'm just going to take it easy this winter and focus on finishing some higher level titles with Nikon and do the fostering thing for a while.
I don't regret owning Pan or the decision to sell him and like I said, the fighting was really only one aspect of that decision. He is just a better fit where he is now. I've never been attached to him the way that I am to Nikon and Coke. It's not Pan's fault he's just a different dog and I got him for different reasons than Nikon and Coke. I had hoped to compete with him at a much higher level and it was hard letting that go but I realized it's selfish of me to keep a dog under stress simply as my project rather than my pet. His new owner is a better trainer than I am and Pan will be in a great club that is already familiar with his pedigree.