starlucia, I'm completely on your side as far as neutering animals, 100%, with the number of unwanted animals killed in 'shelters' as the result of their owner's irresponsibility/bizarre ideas about 'nature', there is no excuse for not neutering/spaying.
bebero, you don't really think your dogs are sweet because they are not neutered, do you? If your dogs are sweet and well behaved and nonaggressive, I think it's far more likely the result of your raising them well with love and limits, not as a result of your choice not to neuter them.
The choice to neuter/spay because it's the conscientious and responsible thing to do is a separate issue from a particular dog's behavior. I have met non-neutered dogs that are totally nonagressive, at least to humans and other dogs, not referring to the breeding situation, obviously, and I have seen plenty of neutered dogs that were VERY aggressive. I think the idea that neutering changes the dog's essential nature is misguided; it's a more complex dominance interaction that takes place between pack animals, probably more complex with a mix of neutered and nonneutered animals.
I was a dogwalker for many years and what I noticed often was neutered dogs reacting to the presence of non-neutered dogs, who were more unusual in San Francisco, and that would manifest differently depending on the dog, whether they (the neutered dog) would behave fearfully or make a preemptive strike on the non-neutered dog. I would imagine the presence of SO MANY non-neutered dogs might be unsettling to your dog, and I would guess expat dogs, at least from the US, are more likely to be neutered.
I had a spayed female dog for eight years, the light of my life, and how she LOVED non-neutered male dogs, acted like she was in heat and of course they could not have cared less about her, poor thing! She could be aggressive with neutered males and other females, don't know whether there was a pattern if the females were spayed or not.
No dogs right now, though we did bring our two 18 year old cats with us, talk about poor things! how they hate the food here, too just like so many expats! Anyone found a source of decent canned cat food not outrageously expensive, ha ha ha?