I would like to draw your attention to a very delicate point, which is the huge difference between being good and loving goodness. Al-Fitrah is manifested in loving goodness, whereas being good is a trait acquired by man himself (Sibghah).

﴾[Our Sibghah (religion) is] the Sibghah (Religion) of Allah (Islam) and which Sibghah (religion) can be better than Allah's?﴿

[Al-Baqarah, 138]

 In fact, every human being loves justice, but he only loves it, so he might be an oppressor. Also, man in general loves mercy, but he might be cruel, and although he loves chastity, he might be a fornicator. However, the minute man establishes a connection with Allah the Almighty and taints his soul with a perfection derived from Allah's Perfection, only then Sibghah replaces Fitrah and takes over. This connection makes him just besides loving justice, and it makes him merciful besides loving mercy.

 Accordingly, we should differentiate between Fitrah and Sibghah, for Sibghah marks the believers who got acquainted with Allah the Almighty, who knew His Method and who obeyed Him, and so their souls feel the Love of Allah towards them, which makes them seek His Content. Furthermore, they derive perfection from Allah's Perfection, given exalted morals are in the Hand of Allah the Almighty, and it is mentioned in the following relic that:

((When He loves one of His servants, He bestows upon him good manners.))

 Basically, Fitrah is installed in souls, which are molded to love perfection. However, being perfect or not is another issue.