Normalizing trauma is not the same thing as not being traumatized. There is an inherent part of Human nature that resists being treated negatively and being exposed to pain. Rats and birds and monkeys resist being hurt, and they do not have the capacity to understand they are being abused. They still learn how to avoid getting hurt, and will adopt behaviors that ensure they receive the least amount of pain and suffering.
Humans are the same way. Just because someone thinks it is normal to get hit does not mean that they will not avoid trying to be hit. They know they do not like it, they know it is negative, they know it hurts, they know they don't want it. Kids resist doing things they don't want all the time. Whether or not you perceive your trauma as normal, or even traumatizing, has absolutely no bearing on whether or not you develop PTSD. I don't mean to offend or upset anybody by saying that it is just something I know from both personal experience and observation. Just because someone considers their way of life normal does not take away the fact that it causes them suffering. Normalizing suffering does not make it any less painful. That is why I tied it into my statements earlier, saying that it is not possible to build a tolerant level of exposure to trauma. Even if you consider the trauma normal, it still would not have an effect on whether or not you developed PTSD.
Soldiers are exposed to combat for months and years at a time, it becomes their way of life, but there is still no level of combat that suddenly makes it all right. That suddenly makes it less intense, that makes it less upsetting, less visceral. Unless a person has a reduced capacity for stress, for physical pain, they are going to find it arduous and probably terrifying. They will probably gradually get used to the terror itself, until the fear itself diminishes bit by bit, replacing itself with anger and tension. But the adrenaline, the hypervigilance, the alertness, the anger, the fuel - that does not go away ever. Your body reacts the exact same every single time until you are too exhausted to move.