How do those who permit a woman to travel without a mahram explain the hadiths that prohibit it?

Some jurists have permitted a woman to travel without a mahram for the obligatory Hajj and the compulsory 'Umrah, citing certain texts. However, this absolute permission is questionable, because the general texts indicate the prohibition of a woman traveling without a mahram. Furthermore, some of the texts they cited do not indicate the permissibility of travel without a mahram; rather, they indicate that it occurred, or they have a specific interpretation. Also, some of the wives of the Prophet (peace and blessings be upon him) did not perform Hajj after him, adhering to a prophetic command, and the travels of the Mothers of the Believers were undertaken with the utmost caution and circumspection.