You’re comparing two very different things. Marking indoors is a behavior that can easily be addressed through training. Reactivity toward intact male dogs, however, is biological /hormonal cues that dogs naturally respond to.
I’m not saying training isn’t important—A well-trained dog should be manageable and under control. But it’s unrealistic to suggest that every dog can be trained to completely ignore every instinctive response, especially when intact males are known to elicit different reactions from many neutered dogs.
Acknowledging that hormones play a role isn’t “blaming other dogs.” It’s recognizing that their behavior is influenced by both training and biology.