According to the Talmud (Megillah 12b) this decree made the king seem foolish in the eyes of the people. They thought to themselves, “This king is a fool! He has to tell me that I rule my home? Ha! Even the lowest laborer rules his shack.” This, in turn, allowed for future decrees to be treated irreverently. If the king is saying foolish things in this instance, future edicts can also be ignored. In particular, the decree to exterminate the Jews (Esther 3:13) could have been taken more seriously, with the Persians preparing for the big day by stockpiling weapons, planning an assault strategy, and beginning the process of choosing and harassing their prey.
Another reason for the people’s perspective on the decree is, as Rav Soloveitchik writes in Days of Deliverance (pg. 59), that if a woman is strong, “she will dominate her husband regardless of the royal decree.”
According to Megillas Sesarim, Achashverosh’s decree restricted the citizens’ influence over the home, in effect telling them that only the king can tell them when to attack the Jews. Along those lines, it could be that since it was a given before this edict that men rule their homes, and the king’s having to command it meant that nothing was a given anymore. Therefore, a “given” conventional wisdom like “it’s perfectly acceptable to terrorize the Jews” was no longer a given, and this is why the people refrained from doing so.