Why are both groups described as having "no sin"?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

1. The meaning is that the one who hastens is excused, and the one who delays is rewarded. The phrase "no sin upon him" was used the second time to match the wording of the first part, similar to the verse: "So whoever has assaulted you, then assault him in the same way that he has assaulted you." (2:194)
2. The meaning is that there is no sin on the one who delays for not availing himself of the concession.
3. The meaning is that the sins of both the one who hastens and the one who delays, which they were bearing before performing Ḥajj, have been removed.
4. The meaning is that the removal of sin for both the one who hastens and the one who delays is conditional upon their piety.