Dorian's life changed after his awakening. His profession was Holy Knight and more than that, he gained a system on the day of his awakening. Through his system, he acquired Light Affinity.
He has learned that the chances of awakening a profession were low among commoners when compared to the nobles. That day he learned that having an affinity is very rare, even among the nobles.
Having an affinity would essentially make the awakener reach the status of a noble, as long as he survives and grows up.
This is a dangerous world after all, and there are monsters everywhere that can end you before you know it. More than that, there are many bad people who are envious of their peers who are more talented than them. they would turn to evil, even hurting their own people, just to become powerful.
Even if they aren't evil, many nobles hate it when the commoners try to offend them. They could easily eliminate the commoner alongside their family.