My male dog bit me when he’s in reactive mode, but never bit me when he’s not

hi guys, I have a question. I tried asking google, but nothing what I’m looking for. okay so I have a male cream Shiba Inu who is 2. my brother also has a male Shiba Inu who is 3. we live under the same home and have separated the backyard with a fence so each one has their side with a privacy gate cover because our dogs would be aggressive and reactive towards each other. I also have another male Shiba inu who is 11 months and my males never fiught with each other with the intent to kill or grab each other’s neck. However, my brother‘s dog and mine would actually try to kill each other if we let them on the same side of the fence. it’s a concern, however, since my dog gets triggered by his dog whenever we try to separate them from the fence, my dog has bitten me because he’s in the middle of the zone of being reactive/agression because the other dog triggered him. When he is not triggered by my brother‘s dog, he’s the sweetest baby and is very sweet with his other companions. So my question is, is he really considered aggressive and bad that he’s only bit me when hes in reactive mode because of the other dog? But would never bite me out of nowhere? My brothers dog is aggressive too, but towards all my dogs, is mine just trying to protect his pack since he’s the alpha of his little pack? He has never bit me out of the blue at all