Those two women—the late emperor's empress and the adoptive mother—were both mountains that Lu Heng was pressed under. And both women were not his biological mothers.
Moreover, after becoming the emperor, Bo Ying kept reminding him of the words, "Legitimate and illegitimate have clear honor and inferiority."
What does this mean? It means that he was not his imperial father's legitimate child but an illegitimate one, so he has to know the difference between superiority and inferiority, the difference between honor and dishonor.
Lu Heng really hates it when others talk about his past. Even if he were adopted by his imperial father's favorite concubine, it would still not change his past experiences or how he was born to be who he is today. He is still his imperial father's illegitimate child, not born of the empress.
