How authentic is the statement attributed to Imam Al-Shafi'i: "Three types, if you honor them, they will humiliate you, and if you humiliate them, they will honor you: women, servants, and Nabataeans," and what does it mean?

Al-Ghazali mentioned in "Al-Ihya" that the phrase "Honor them but do not teach them writing" means that honor should not be mixed with harshness, and it does not mean not honoring them or humiliating them, because Islam commands honoring women and servants. The intention is justice in this matter, for everything that exceeds its limit turns into its opposite, and one should follow the path of moderation and adhere to the truth. And it was said: "Do not be so soft that you are squeezed, nor so hard that you are broken."