Pasargad, the capital of Cyrus the Great, is the only capital without ancient defensive fortifications

All over the world, all the capitals of different countries had military fortifications
Pasargad, the capital of Cyrus the Great, is the only city that did not have military fortifications such as military towers and ramparts, and there was practically no sign of defense measures up to the gate, but why is Pasargad so different?
According to Prof. David Stronach, University of California, Cyrus the Great wanted to show two things by removing the defensive role. :
1-The power of his own empire, in which there was no need for a military garrison
2-He also spoke of the benevolence and humility of the ruler who welcomed people instead of driving them away from his house
It is not without reason that the Iranians called Cyrus the father of the Jews, the Messiah and the savior, and the Greeks called him the ruler and lawgiver.